Make some waypoint types undraggable.

None of these (takeoff, landing, divert, bullseye, precise target
locations) can be usefully moved, so prevent it.

qt_ui/widgets/map/mapmodel.py

@@ -379,7 +379,9 @@ class WaypointJs(QObject):
     altitudeReferenceChanged = Signal()
     nameChanged = Signal()
     timingChanged = Signal()
+    isTargetPointChanged = Signal()
     isTakeoffChanged = Signal()
+    isLandingChanged = Signal()
     isDivertChanged = Signal()
     isBullseyeChanged = Signal()
 
@@ -438,10 +440,18 @@ class WaypointJs(QObject):
             return ""
         return f"{prefix} T+{timedelta(seconds=int(time.total_seconds()))}"
 
+    @Property(bool, notify=isTargetPointChanged)
+    def isTargetPoint(self) -> bool:
+        return self.waypoint.waypoint_type is FlightWaypointType.TARGET_POINT
+
     @Property(bool, notify=isTakeoffChanged)
     def isTakeoff(self) -> bool:
         return self.waypoint.waypoint_type is FlightWaypointType.TAKEOFF
 
+    @Property(bool, notify=isLandingChanged)
+    def isLanding(self) -> bool:
+        return self.waypoint.waypoint_type is FlightWaypointType.LANDING_POINT
+
     @Property(bool, notify=isDivertChanged)
     def isDivert(self) -> bool:
         return self.waypoint.waypoint_type is FlightWaypointType.DIVERT