Fix purchase groups.

The new class PurchaseGroup coming in with commit 9bb986c was not
initiallized correctly.

This causes the bug that the update function is not working when you
for example open the AircraftRecruitmentMenu press "+" or "-", close
the dialog and then open ArmorRecruitmentMenu. If you then want to buy
or sell the update function will raise an error "Internal C++ Object
Already Deleted".

qt_ui/windows/basemenu/QRecruitBehaviour.py

@@ -76,13 +76,14 @@ class PurchaseGroup(QGroupBox):
 class QRecruitBehaviour:
     game_model: GameModel
     cp: ControlPoint
-    purchase_groups: dict[UnitType, PurchaseGroup] = {}
+    purchase_groups: dict[UnitType, PurchaseGroup]
     existing_units_labels = None
     maximum_units = -1
     BUDGET_FORMAT = "Available Budget: <b>${:.2f}M</b>"
 
     def __init__(self) -> None:
         self.existing_units_labels = {}
+        self.purchase_groups = {}
         self.update_available_budget()
 
     @property

qt_ui/windows/basemenu/airfield/QAircraftRecruitmentMenu.py

@@ -26,7 +26,7 @@ class QAircraftRecruitmentMenu(QFrame, QRecruitBehaviour):
         QFrame.__init__(self)
         self.cp = cp
         self.game_model = game_model
-
+        self.purchase_groups = {}
         self.bought_amount_labels = {}
         self.existing_units_labels = {}
 

qt_ui/windows/basemenu/ground_forces/QArmorRecruitmentMenu.py

@@ -18,7 +18,7 @@ class QArmorRecruitmentMenu(QFrame, QRecruitBehaviour):
         QFrame.__init__(self)
         self.cp = cp
         self.game_model = game_model
-
+        self.purchase_groups = {}
         self.bought_amount_labels = {}
         self.existing_units_labels = {}