Add arabic test typeface

tests/Avalonia.Skia.UnitTests/Media/CustomFontManagerImpl.cs

@@ -15,6 +15,8 @@ namespace Avalonia.Skia.UnitTests.Media
 
         private readonly Typeface _defaultTypeface =
             new Typeface("resm:Avalonia.Skia.UnitTests.Assets?assembly=Avalonia.Skia.UnitTests#Noto Mono");
+        private readonly Typeface _arabicTypeface =
+           new Typeface("resm:Avalonia.Skia.UnitTests.Assets?assembly=Avalonia.Skia.UnitTests#Noto Kufi Arabic");
         private readonly Typeface _italicTypeface =
             new Typeface("resm:Avalonia.Skia.UnitTests.Assets?assembly=Avalonia.Skia.UnitTests#Noto Sans", FontStyle.Italic);
         private readonly Typeface _emojiTypeface =
@@ -22,7 +24,7 @@ namespace Avalonia.Skia.UnitTests.Media
 
         public CustomFontManagerImpl()
         {
-            _customTypefaces = new[] { _emojiTypeface, _italicTypeface, _defaultTypeface };
+            _customTypefaces = new[] { _emojiTypeface, _italicTypeface, _arabicTypeface, _defaultTypeface };
             _defaultFamilyName = _defaultTypeface.FontFamily.FamilyNames.PrimaryFamilyName;
         }