Don't tell the UI about CP TGOs.

These are an implementation quirk, and passing them to the UI just means
that we put TGO pins on top of the CP, which makes the base menu
unopenable.

In the old UI we avoided this by not drawing anything that was
`for_airbase`, but now that we can zoom in further we're drawing base
defenses.

qt_ui/widgets/map/mapmodel.py

@@ -517,6 +517,11 @@ class MapModel(QObject):
                     continue
                 seen.add(tgo.name)
 
+                if tgo.is_control_point:
+                    # TGOs that are the CP (CV groups) are an implementation quirk that
+                    # we don't need to expose to the UI.
+                    continue
+
                 self._ground_objects.append(GroundObjectJs(tgo, self.game))
         self.groundObjectsChanged.emit()