fix: Avoid infinite layout loop in MediaTransportControls

Subscription to LayoutUpdated caused it to loop infinitely as it manipulated margins of inner controls, which then triggered another layout loop, which reset them again

src/Uno.UI/UI/Xaml/Controls/MediaPlayerElement/MediaTransportControls.cs

@@ -539,7 +539,6 @@ private void OnCommandBarLoaded(object? sender, RoutedEventArgs e)
 			if (m_tpCommandBar is not null)
 			{
 				m_tpCommandBar.Loaded -= OnCommandBarLoaded;
-				this.LayoutUpdated += MediaTransportControls_LayoutUpdated;
 				m_tpCommandBar.SizeChanged += Container_SizeChanged;
 				m_tpCommandBar.DynamicOverflowItemsChanging += M_tpCommandBar_DynamicOverflowItemsChanging;
 			}
@@ -551,10 +550,6 @@ private void OnCommandBarLoaded(object? sender, RoutedEventArgs e)
 			HideCastButtonIfNecessary();
 		}
 
-		private void MediaTransportControls_LayoutUpdated(object? sender, object e)
-		{
-			SetMeasureCommandBar();
-		}
 		private void M_tpCommandBar_DynamicOverflowItemsChanging(CommandBar sender, DynamicOverflowItemsChangingEventArgs args)
 		{
 			SetMeasureCommandBar();