UI: Fix empty homebrew icon (#5189)

* UI: Fix empty homebrew icon

We currently don't check the icon size when we read it from the homebrew data. That could cause issues at UI side since the buffer isn't null but empty. Extra check have been added UI side too.
(I cleaned up some files during my research too)

Fixes #5188

* Remove additional check

* Remove unused using

src/Ryujinx.Ava/UI/Helpers/BitmapArrayValueConverter.cs

@@ -21,6 +21,7 @@ namespace Ryujinx.Ava.UI.Helpers
             if (value is byte[] buffer && targetType == typeof(IImage))
             {
                 MemoryStream mem = new(buffer);
+
                 return new Bitmap(mem);
             }