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/Crayon/UI/CrayonWindow.xaml.cs

@@ -53,7 +53,7 @@ namespace Content.Client.Crayon.UI
         private void RefreshList()
         {
             // Clear
-            Grids.DisposeAllChildren();
+            Grids.RemoveAllChildren();
 
             if (_decals == null || _allDecals == null)
                 return;