fix: support WASM.

demo/Ursa.Demo.Browser/App.axaml

@@ -1,9 +0,0 @@
-<Application
-    x:Class="Ursa.Demo.Browser.App"
-    xmlns="https://github.com/avaloniaui"
-    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
-    <Application.Styles>
-        <StyleInclude Source="avares://Semi.Avalonia/Themes/Index.axaml" />
-        <StyleInclude Source="avares://Ursa.Themes.Semi/Index.axaml" />
-    </Application.Styles>
-</Application>

demo/Ursa.Demo.Browser/App.axaml.cs

@@ -1,23 +0,0 @@
-using Avalonia;
-using Avalonia.Controls.ApplicationLifetimes;
-using Avalonia.Markup.Xaml;
-using Ursa.Demo.Views;
-
-namespace Ursa.Demo.Browser;
-
-public partial class App : Application
-{
-    public override void Initialize()
-    {
-        AvaloniaXamlLoader.Load(this);
-    }
-
-    public override void OnFrameworkInitializationCompleted()
-    {
-        if (ApplicationLifetime is ISingleViewApplicationLifetime single)
-        {
-            single.MainView = new MainView();
-        }
-        base.OnFrameworkInitializationCompleted();
-    }
-}