Revert upgrade to pyside6.

This appears to be incompatible with pyinstaller. I get the following
when trying to run the executable generated with pyside6:

```
Traceback (most recent call last):
  File "qt_ui\main.py", line 29, in <module>
  File "PyInstaller\loader\pyimod03_importers.py", line 476, in exec_module
  File "qt_ui\windows\QLiberationWindow.py", line 28, in <module>
  File "PyInstaller\loader\pyimod03_importers.py", line 476, in exec_module
  File "qt_ui\widgets\map\QLiberationMap.py", line 11, in <module>
ImportError: could not import module 'PySide6.QtPrintSupport'
```

qt_ui/widgets/QBudgetBox.py

@@ -1,4 +1,4 @@
-from PySide6.QtWidgets import QLabel, QHBoxLayout, QGroupBox, QPushButton
+from PySide2.QtWidgets import QLabel, QHBoxLayout, QGroupBox, QPushButton
 
 import qt_ui.uiconstants as CONST
 from game import Game

qt_ui/widgets/QConditionsWidget.py

@@ -1,7 +1,7 @@
 from datetime import datetime
 
-from PySide6.QtGui import QPixmap
-from PySide6.QtWidgets import (
+from PySide2.QtGui import QPixmap
+from PySide2.QtWidgets import (
     QFrame,
     QGridLayout,
     QGroupBox,

qt_ui/widgets/QDebriefingInformation.py

@@ -1,4 +1,4 @@
-from PySide6.QtWidgets import QFrame
+from PySide2.QtWidgets import QFrame
 
 
 class QDebriefingInformation(QFrame):

qt_ui/widgets/QFactionsInfos.py

@@ -1,4 +1,4 @@
-from PySide6.QtWidgets import QLabel, QGroupBox, QGridLayout
+from PySide2.QtWidgets import QLabel, QGroupBox, QGridLayout
 from game import Game
 
 

qt_ui/widgets/QFlightSizeSpinner.py

@@ -1,5 +1,5 @@
 """Spin box for selecting the number of aircraft in a flight."""
-from PySide6.QtWidgets import QSpinBox
+from PySide2.QtWidgets import QSpinBox
 
 
 class QFlightSizeSpinner(QSpinBox):

qt_ui/widgets/QIntelBox.py

@@ -1,6 +1,6 @@
 from typing import Optional
 
-from PySide6.QtWidgets import (
+from PySide2.QtWidgets import (
     QGridLayout,
     QGroupBox,
     QHBoxLayout,

qt_ui/widgets/QLabeledWidget.py

@@ -1,8 +1,8 @@
 """A layout containing a widget with an associated label."""
 from typing import Optional
 
-from PySide6.QtCore import Qt
-from PySide6.QtWidgets import QHBoxLayout, QLabel, QWidget
+from PySide2.QtCore import Qt
+from PySide2.QtWidgets import QHBoxLayout, QLabel, QWidget
 
 
 class QLabeledWidget(QHBoxLayout):

qt_ui/widgets/QLiberationCalendar.py

@@ -1,5 +1,5 @@
-from PySide6 import QtCore, QtGui
-from PySide6.QtWidgets import QCalendarWidget
+from PySide2 import QtCore, QtGui
+from PySide2.QtWidgets import QCalendarWidget
 
 
 class QLiberationCalendar(QCalendarWidget):

qt_ui/widgets/QTopPanel.py

@@ -1,6 +1,6 @@
 from typing import List, Optional
 
-from PySide6.QtWidgets import (
+from PySide2.QtWidgets import (
     QDialog,
     QFrame,
     QGroupBox,

qt_ui/widgets/ato.py

@@ -3,18 +3,18 @@ import logging
 from datetime import timedelta
 from typing import Optional
 
-from PySide6.QtCore import (
+from PySide2.QtCore import (
     QItemSelectionModel,
     QModelIndex,
     QSize,
     Qt,
 )
-from PySide6.QtGui import (
-    QAction,
+from PySide2.QtGui import (
     QContextMenuEvent,
 )
-from PySide6.QtWidgets import (
+from PySide2.QtWidgets import (
     QAbstractItemView,
+    QAction,
     QGroupBox,
     QHBoxLayout,
     QLabel,

qt_ui/widgets/clientslots.py

@@ -1,5 +1,5 @@
 """Widgets for displaying client slots."""
-from PySide6.QtWidgets import QLabel
+from PySide2.QtWidgets import QLabel
 
 from qt_ui.models import AtoModel
 from qt_ui.widgets.QLabeledWidget import QLabeledWidget

qt_ui/widgets/combos/QAircraftTypeSelector.py

@@ -1,7 +1,7 @@
 """Combo box for selecting aircraft types."""
 from typing import Iterable, Type
 
-from PySide6.QtWidgets import QComboBox
+from PySide2.QtWidgets import QComboBox
 from dcs.unittype import FlyingType
 
 from gen.flights.ai_flight_planner_db import aircraft_for_task

qt_ui/widgets/combos/QArrivalAirfieldSelector.py

@@ -1,7 +1,7 @@
 """Combo box for selecting a departure airfield."""
 from typing import Iterable, Optional
 
-from PySide6.QtWidgets import QComboBox
+from PySide2.QtWidgets import QComboBox
 from dcs.unittype import FlyingType
 
 from game.dcs.aircrafttype import AircraftType

qt_ui/widgets/combos/QFilteredComboBox.py

@@ -1,5 +1,5 @@
-from PySide6.QtCore import QSortFilterProxyModel, Qt
-from PySide6.QtWidgets import QComboBox, QCompleter
+from PySide2.QtCore import QSortFilterProxyModel, Qt
+from PySide2.QtWidgets import QComboBox, QCompleter
 
 
 class QFilteredComboBox(QComboBox):

qt_ui/widgets/combos/QFlightTypeComboBox.py

@@ -1,6 +1,6 @@
 """Combo box for selecting a flight's task type."""
 
-from PySide6.QtWidgets import QComboBox
+from PySide2.QtWidgets import QComboBox
 
 from game.theater import ConflictTheater, MissionTarget
 

qt_ui/widgets/combos/QPredefinedWaypointSelectionComboBox.py

@@ -1,4 +1,4 @@
-from PySide6.QtGui import QStandardItem, QStandardItemModel
+from PySide2.QtGui import QStandardItem, QStandardItemModel
 
 from game import Game
 from game.theater import ControlPointType, BuildingGroundObject

qt_ui/widgets/combos/QStrikeTargetSelectionComboBox.py

@@ -1,4 +1,4 @@
-from PySide6.QtGui import QStandardItem, QStandardItemModel
+from PySide2.QtGui import QStandardItem, QStandardItemModel
 
 from game import Game
 from qt_ui.widgets.combos.QFilteredComboBox import QFilteredComboBox

qt_ui/widgets/floatspinners.py

@@ -1,6 +1,6 @@
 from typing import Optional
 
-from PySide6.QtWidgets import QSpinBox
+from PySide2.QtWidgets import QSpinBox
 
 
 class FloatSpinner(QSpinBox):

qt_ui/widgets/map/QLiberationMap.py

@@ -6,10 +6,10 @@ from typing import (
     Optional,
 )
 
-from PySide6.QtCore import QUrl
-from PySide6.QtWebChannel import QWebChannel
-from PySide6.QtWebEngineCore import QWebEnginePage
-from PySide6.QtWebEngineWidgets import (
+from PySide2.QtCore import QUrl
+from PySide2.QtWebChannel import QWebChannel
+from PySide2.QtWebEngineWidgets import (
+    QWebEnginePage,
     QWebEngineView,
 )
 
@@ -27,7 +27,6 @@ class LoggingWebPage(QWebEnginePage):
         line_number: int,
         source: str,
     ) -> None:
-        super().javaScriptConsoleMessage(level, message, line_number, source)
         if level == QWebEnginePage.JavaScriptConsoleMessageLevel.ErrorMessageLevel:
             logging.error(message)
         elif level == QWebEnginePage.JavaScriptConsoleMessageLevel.WarningMessageLevel:
@@ -49,11 +48,11 @@ class QLiberationMap(QWebEngineView):
         self.channel.registerObject("game", self.map_model)
 
         self.page = LoggingWebPage(self)
-        self.setPage(self.page)
         self.page.setWebChannel(self.channel)
         self.page.load(
             QUrl.fromLocalFile(str(Path("resources/ui/map/canvas.html").resolve()))
         )
+        self.setPage(self.page)
 
     def set_game(self, game: Optional[Game]) -> None:
         if game is None:

qt_ui/widgets/map/mapmodel.py

@@ -4,7 +4,7 @@ import logging
 from datetime import timedelta
 from typing import Iterator, List, Optional, Tuple, Union
 
-from PySide6.QtCore import Property, QObject, Signal, Slot
+from PySide2.QtCore import Property, QObject, Signal, Slot
 from dcs import Point
 from dcs.unit import Unit
 from dcs.vehicles import vehicle_map
@@ -59,7 +59,7 @@ ENABLE_EXPENSIVE_DEBUG_TOOLS = False
 #
 # https://bugreports.qt.io/browse/PYSIDE-1426
 #
-# PySide6 5.15.2 released 6 days before the fix for this was merged, but presumably we
+# PySide2 5.15.2 released 6 days before the fix for this was merged, but presumably we
 # can clean up after 5.15.3 (or a future version) is released.
 #
 # Until then, all properties must use a notify signal. For some reason the error doesn't

qt_ui/widgets/simspeedcontrols.py

@@ -2,7 +2,7 @@ from __future__ import annotations
 
 from typing import Optional
 
-from PySide6.QtWidgets import QButtonGroup, QHBoxLayout, QPushButton, QWidget
+from PySide2.QtWidgets import QButtonGroup, QHBoxLayout, QPushButton, QWidget
 
 from game.sim.simspeedsetting import SimSpeedSetting
 from qt_ui.simcontroller import SimController

qt_ui/widgets/spinsliders.py

@@ -1,9 +1,9 @@
 from datetime import timedelta
 from typing import Optional
 
-from PySide6 import QtWidgets
-from PySide6.QtCore import Qt
-from PySide6.QtWidgets import QSlider, QHBoxLayout
+from PySide2 import QtWidgets
+from PySide2.QtCore import Qt
+from PySide2.QtWidgets import QSlider, QHBoxLayout
 
 from qt_ui.widgets.floatspinners import FloatSpinner
 

qt_ui/widgets/views/QStrikeTargetInfoView.py

@@ -1,7 +1,7 @@
 import random
 
-from PySide6.QtGui import QStandardItemModel, QStandardItem
-from PySide6.QtWidgets import (
+from PySide2.QtGui import QStandardItemModel, QStandardItem
+from PySide2.QtWidgets import (
     QGroupBox,
     QLabel,
     QWidget,