make win.ui.comp the default when running on win10 and compatible gpu is used.

samples/ControlCatalog.NetCore/Program.cs

@@ -117,8 +117,7 @@ namespace ControlCatalog.NetCore
                 .With(new Win32PlatformOptions
                 {
                     EnableMultitouch = true,
-                    AllowEglInitialization = true,
-                    UseWindowsUIComposition = true
+                    AllowEglInitialization = true
                 })
                 .UseSkia()
                 .UseReactiveUI()

src/Windows/Avalonia.Win32/Win32Platform.cs

@@ -47,7 +47,7 @@ namespace Avalonia
         /// Supported on Windows 10 build 16299 and above. Ignored on other versions.
         /// This is recommended if you need to use AcrylicBlur or acrylic in your applications.
         /// </remarks>
-        public bool UseWindowsUIComposition { get; set; }
+        public bool UseWindowsUIComposition { get; set; } = true;
     }
 }