chore: build errors

src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Input/Keyboard/Keyboard_Modifiers.xaml.cs

@@ -11,7 +11,9 @@ namespace UITests.Windows_UI_Xaml_Input.Keyboard
 	[Sample("Keyboard", IsManualTest = true)]
 	public sealed partial class Keyboard_Modifiers : Page
 	{
+#if HAS_UNO
 		private DispatcherTimer _timer;
+#endif
 
 		public Keyboard_Modifiers()
 		{