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

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

* Remove duplicate calls.

---------

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

Content.Client/Salvage/UI/OfferingWindow.xaml.cs

@@ -70,7 +70,7 @@ public sealed partial class OfferingWindow : FancyWindow,
 
     public void ClearOptions()
     {
-        Container.DisposeAllChildren();
+        Container.RemoveAllChildren();
     }
 
     protected override void FrameUpdate(FrameEventArgs args)