feat: enable vulkan in android demo.

demo/Semi.Avalonia.Demo.Android/MainActivity.cs

@@ -1,5 +1,6 @@
 using Android.App;
 using Android.Content.PM;
+using Avalonia;
 using Avalonia.Android;
 
 namespace Semi.Avalonia.Demo.Android;
@@ -13,4 +14,12 @@ namespace Semi.Avalonia.Demo.Android;
     ConfigurationChanges = ConfigChanges.Orientation | ConfigChanges.ScreenSize | ConfigChanges.UiMode)]
 public class MainActivity : AvaloniaMainActivity<App>
 {
+    protected override AppBuilder CustomizeAppBuilder(AppBuilder builder)
+    {
+        return base.CustomizeAppBuilder(builder)
+            .With(new AndroidPlatformOptions()
+            {
+                RenderingMode = [AndroidRenderingMode.Vulkan, AndroidRenderingMode.Egl, AndroidRenderingMode.Software]
+            });
+    }
 }