Ensure border stroke does not regenerate on Parent or Window property…

… changes (#24125)

Co-authored-by: Mike Corsaro <mikecorsaro@microsoft.com>

src/Controls/src/Core/Border/Border.cs

@@ -65,7 +65,14 @@ void NotifyStrokeShapeChanges()
 			if (strokeShape is VisualElement visualElement)
 			{
 				AddLogicalChild(visualElement);
-				_strokeShapeChanged ??= (sender, e) => OnPropertyChanged(nameof(StrokeShape));
+				_strokeShapeChanged ??= (sender, e) =>
+				{
+					if (e.PropertyName != nameof(Window) &&
+						e.PropertyName != nameof(Parent))
+					{
+						OnPropertyChanged(nameof(StrokeShape));
+					}
+				};
 				_strokeShapeProxy ??= new();
 				_strokeShapeProxy.Subscribe(visualElement, _strokeShapeChanged);
 			}