fix: Adjust NativeFramePresenter to work with new TemplatedParent (…

…#1266)

(cherry picked from commit f704393)

src/Uno.Toolkit.UI/Controls/NavigationBar/NativeFramePresenter.Android.cs

@@ -45,12 +45,13 @@ public partial class NativeFramePresenter : Grid // Inheriting from Grid is a ha
 		public NativeFramePresenter()
 		{
 			_pageStack = this;
+
+			this.Loaded += OnLoaded;
 		}
 
-		protected override void OnTemplatedParentChanged(DependencyPropertyChangedEventArgs e)
+		private void OnLoaded(object sender, RoutedEventArgs e)
 		{
-			base.OnTemplatedParentChanged(e);
-			Initialize(TemplatedParent as Frame);
+			Initialize(this.FindFirstParent<Frame>());
 		}
 
 		private void Initialize(Frame? frame)

src/Uno.Toolkit.UI/Controls/NavigationBar/NativeFramePresenter.iOS.cs

@@ -107,12 +107,12 @@ public NativeFramePresenter()
 			SizeChanged += NativeFramePresenter_SizeChanged;
 			// Hide the NavigationBar by default. Only show if navigating to a Page that contains a NavigationBar.
 			NavigationController.NavigationBarHidden = true;
+			this.Loaded += OnLoaded;
 		}
 
-		protected override void OnTemplatedParentChanged(DependencyPropertyChangedEventArgs e)
+		private void OnLoaded(object sender, RoutedEventArgs e)
 		{
-			base.OnTemplatedParentChanged(e);
-			InitializeController(TemplatedParent as Frame);
+			InitializeController(this.FindFirstParent<Frame>());
 		}
 
 		/// <summary>