Avalonia: Another Cleanup (#3494)

* Avalonia: Another Cleanup

This PR is a cleanup to the avalonia code recently added:

- Some XAML file are autoformatted like a previous PR.
- Dlc is renamed to DownloadableContent (Locale exclude).
- DownloadableContentManagerWindow is a bit improved (Fixes #3491).
- Some nits here and there.

* Fix GTK

* Remove AttachDebugDevTools

* Fix last warning

* Fix JSON fields

Ryujinx.Ava/Ui/ViewModels/AmiiboWindowViewModel.cs

@@ -382,9 +382,9 @@ namespace Ryujinx.Ava.Ui.ViewModels
             {
                 string amiiboJsonString = await response.Content.ReadAsStringAsync();
 
-                using (FileStream dlcJsonStream = File.Create(_amiiboJsonPath, 4096, FileOptions.WriteThrough))
+                using (FileStream amiiboJsonStream = File.Create(_amiiboJsonPath, 4096, FileOptions.WriteThrough))
                 {
-                    dlcJsonStream.Write(Encoding.UTF8.GetBytes(amiiboJsonString));
+                    amiiboJsonStream.Write(Encoding.UTF8.GetBytes(amiiboJsonString));
                 }
 
                 return amiiboJsonString;