[macOS/iOS] Fix RequestedThemeChanged event (#11199) (#14077)

Co-authored-by: Javier Suárez <javiersuarezruiz@hotmail.com>
Co-authored-by: Gerald Versluis <gerald.versluis@microsoft.com>
Co-authored-by: Rui Marinho <me@ruimarinho.net>
Co-authored-by: Manuel de la Pena <mandel@microsoft.com>
Co-authored-by: Matthew Leibowitz <mattleibow@live.com>

src/Controls/src/Core/Compatibility/Handlers/Shell/iOS/ShellSectionRootRenderer.cs

@@ -5,6 +5,7 @@
 using CoreAnimation;
 using CoreGraphics;
 using Foundation;
+using Microsoft.Extensions.DependencyInjection;
 using ObjCRuntime;
 using UIKit;
 
@@ -129,7 +130,13 @@ public override void ViewSafeAreaInsetsDidChange()
 			LayoutHeader();
 		}
 
+		public override void TraitCollectionDidChange(UITraitCollection previousTraitCollection)
+		{
+			base.TraitCollectionDidChange(previousTraitCollection);
 
+			var application = _shellContext?.Shell?.FindMauiContext().Services.GetService<IApplication>();
+			application?.ThemeChanged();
+		}
 
 		void IDisconnectable.Disconnect()
 		{

src/Controls/src/Core/PublicAPI/net-ios/PublicAPI.Unshipped.txt

@@ -1,3 +1,4 @@
 #nullable enable
 *REMOVED*override Microsoft.Maui.Controls.RefreshView.MeasureOverride(double widthConstraint, double heightConstraint) -> Microsoft.Maui.Graphics.Size
 override Microsoft.Maui.Controls.View.ChangeVisualState() -> void
+~override Microsoft.Maui.Controls.Platform.Compatibility.ShellSectionRootRenderer.TraitCollectionDidChange(UIKit.UITraitCollection previousTraitCollection) -> void

src/Controls/src/Core/PublicAPI/net-maccatalyst/PublicAPI.Unshipped.txt

@@ -1,3 +1,4 @@
 #nullable enable
 *REMOVED*override Microsoft.Maui.Controls.RefreshView.MeasureOverride(double widthConstraint, double heightConstraint) -> Microsoft.Maui.Graphics.Size
 override Microsoft.Maui.Controls.View.ChangeVisualState() -> void
+~override Microsoft.Maui.Controls.Platform.Compatibility.ShellSectionRootRenderer.TraitCollectionDidChange(UIKit.UITraitCollection previousTraitCollection) -> void