fix(uielement): [iOS] Fix TransformToVisual output inside ScrollViewer

Fix scroll offset being double-applied to TransformToVisual offset. This fixes Flyouts not being positioned properly when attached to an anchor in scrolled content.

src/SamplesApp/SamplesApp.UITests/Windows_UI_Xaml/UIElementTests/UIElementTests.cs

@@ -16,7 +16,6 @@ public class UIElementTests : SampleControlUITestBase
 		// TODO: convert this to RuntimeTests https://github.com/unoplatform/uno/issues/2114#issuecomment-555209397
 		[Test]
 		[AutoRetry]
-		[ActivePlatforms(Platform.Browser)]
 		public void When_TransformToVisual_Transform()
 		{
 			Run("UITests.Shared.Windows_UI_Xaml.UIElementTests.TransformToVisual_Transform", skipInitialScreenshot: false);
@@ -27,7 +26,6 @@ public void When_TransformToVisual_Transform()
 		// TODO: convert this to RuntimeTests https://github.com/unoplatform/uno/issues/2114#issuecomment-555209397
 		[Test]
 		[AutoRetry]
-		[ActivePlatforms(Platform.Browser)]
 		public void When_TransformToVisual_ScrollViewer()
 		{
 			Run("UITests.Shared.Windows_UI_Xaml.UIElementTests.TransformToVisual_ScrollViewer", skipInitialScreenshot: false);

src/Uno.UI/UI/Xaml/UIElement.iOS.cs

@@ -166,12 +166,14 @@ private bool TryGetParentUIElementForTransformToVisual(out UIElement parentEleme
 								// We found a UIElement in the parent hierarchy, we compute the X/Y offset between the
 								// first parent 'view' and this 'elt', and return it.
 
-								if (view is UICollectionView)
+								if (view is UICollectionView || view is NativeScrollContentPresenter)
 								{
 									// The UICollectionView (ListView) will include the scroll offset when converting point to coordinates
 									// space of the parent, but the same scroll offset will be applied by the parent ScrollViewer.
 									// So as it's not expected to have any transform/margins/etc., we compute offset directly from its parent.
 
+									// The same logic applies to NativeScrollContentPresenter, since the ScrollViewer offsets will be explicitly taken into account.
+
 									view = view.Superview;
 								}