[UIKit] Fix UIKit selector on TvOS (#18617)

This API was missed because the old sim intro tests are not running and
we missed it. This was found while working on xcode15. The tvOS attr is
missing which defaults to the min version of tvOS when it should be 15.

Added a compat implementation so that the API remains.

---------

Co-authored-by: GitHub Actions Autoformatter <github-actions-autoformatter@xamarin.com>
Co-authored-by: Rolf Bjarne Kvinge <rolf@xamarin.com>

src/UIKit/UIMenu.cs

@@ -0,0 +1,38 @@
+#if !WATCH
+using System;
+using System.Runtime.InteropServices;
+
+using ObjCRuntime;
+using Foundation;
+
+namespace UIKit {
+	public partial class UIMenu {
+#if !XAMCORE_5_0
+
+#if NET
+		[SupportedOSPlatform ("tvos15.0")]
+		[SupportedOSPlatform ("ios15.0")]
+		[SupportedOSPlatform ("maccatalyst15.0")]
+#else
+		[iOS (15, 0)]
+		[TV (15,0)]
+#endif
+		public virtual UIMenuElement [] SelectedElements {
+			get {
+				// check if we are on tvos earlier than 15, if so, return and empty array, else return
+				// the correct value
+#if TVOS
+				if (SystemVersion.ChecktvOS (15, 0)) {
+					return _SelectedElements;
+				} else {
+					return Array.Empty<UIMenuElement> ();
+				}
+#else
+				return _SelectedElements;
+#endif
+			}
+#endif
+		}
+	}
+}
+#endif

src/frameworks.sources

@@ -1741,6 +1741,7 @@ UIKIT_SOURCES = \
 	UIKit/UIKeyboard.cs \
 	UIKit/UIKitSynchronizationContext.cs \
 	UIKit/UIListSeparatorConfiguration.cs \
+	UIKit/UIMenu.cs \
 	UIKit/UINavigationBar.cs \
 	UIKit/UINavigationController.cs \
 	UIKit/UIPageViewController.cs \

src/uikit.cs

@@ -9157,9 +9157,14 @@ interface UIMenu {
 		[Export ("options")]
 		UIMenuOptions Options { get; }
 
-		[iOS (15, 0), MacCatalyst (15, 0)]
+		[iOS (15, 0), MacCatalyst (15, 0), TV (15, 0)]
 		[Export ("selectedElements")]
+#if XAMCORE_5_0
 		UIMenuElement [] SelectedElements { get; }
+#else
+		[Internal]
+		UIMenuElement [] _SelectedElements { get; }
+#endif
 
 		[Export ("children")]
 		UIMenuElement [] Children { get; }