UI: Restore FluentAvaloniaUI package, disable animations on app initialization

* Avalonia's built-in color picker is now used when selecting a firmware avatar

src/Ryujinx/App.axaml.cs

@@ -6,6 +6,7 @@ using Avalonia.Platform;
 using Avalonia.Styling;
 using Avalonia.Threading;
 using CommandLine;
+using FluentAvalonia.Core;
 using Ryujinx.Ava.Common;
 using Ryujinx.Ava.Common.Locale;
 using Ryujinx.Ava.UI.Helpers;
@@ -35,6 +36,8 @@ namespace Ryujinx.Ava
         {
             Name = $"Ryujinx {Program.Version}";
 
+            FAUISettings.SetAnimationsEnabledAtAppLevel(false);
+
             AvaloniaXamlLoader.Load(this);
 
             if (OperatingSystem.IsMacOS())