Set ExtendsContentIntoTitleBar only on Windows10+

Author: szv

src/Codebreaker.Uno/CodebreakerUno/Views/Pages/ShellPage.xaml.cs

@@ -13,7 +13,9 @@ public ShellPage(ShellViewModel viewModel)
         ViewModel.NavigationService.Frame = NavigationFrame;
         ViewModel.NavigationViewService.Initialize(NavigationViewControl);
 
+#if WINDOWS10_0_17763_0_OR_GREATER
         App.Current.MainWindow!.ExtendsContentIntoTitleBar = true;
+#endif
         AppTitleBarText.Text = "AppDisplayName".GetLocalized();
     }