Cleanup - Use RemoveAllChildren() over DisposeAllChildren() (#39848)

* Content - change the (should-be-obsolete) DisposeAllChildren into the more robust RemoveAllChildren.

* Remove duplicate calls.

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Co-authored-by: ElectroJr <leonsfriedrich@gmail.com>

Content.Client/Shuttles/UI/MapScreen.xaml.cs

@@ -237,7 +237,7 @@ public sealed partial class MapScreen : BoxContainer
     private void ClearMapObjects()
     {
         _mapObjectControls.Clear();
-        HyperspaceDestinations.DisposeAllChildren();
+        HyperspaceDestinations.RemoveAllChildren();
         _pendingMapObjects.Clear();
         _mapObjects.Clear();
         _mapHeadings.Clear();