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/DockingScreen.xaml.cs

@@ -67,8 +67,8 @@ public sealed partial class DockingScreen : BoxContainer
     {
         DockingControl.BuildDocks(shuttle);
         var currentDock = DockingControl.ViewedDock;
-        // DockedWith.DisposeAllChildren();
-        DockPorts.DisposeAllChildren();
+        // DockedWith.RemoveAllChildren();
+        DockPorts.RemoveAllChildren();
         _ourDockButtons.Clear();
 
         if (shuttle == null)