UIElementExtensions: ClibToBounds defualt UnsetValue -> null

Author: Rosuavio

Microsoft.Toolkit.Uwp.UI/Extensions/UIElementExtensions.cs

@@ -20,7 +20,7 @@ public static class UIElementExtensions
             "ClipToBounds",
             typeof(bool),
             typeof(UIElementExtensions),
-            new PropertyMetadata(DependencyProperty.UnsetValue, OnClipToBoundsPropertyChanged));
+            new PropertyMetadata(null, OnClipToBoundsPropertyChanged));
 
         /// <summary>
         /// Gets the value of <see cref="ClipToBoundsProperty"/>