[Enhancement] Xamarin.Forms.Platform.WPF.ImageExtensions to public (#7462)

* Wpf api changes #7445

* Remove documentation comments

* Chg: C# language is not 7.3
fixes #7445

Xamarin.Forms.Platform.WPF/Extensions/ImageExtensions.cs

@@ -10,7 +10,7 @@ using WImageSource = System.Windows.Media.ImageSource;
 
 namespace Xamarin.Forms.Platform.WPF
 {
-	internal static class ImageExtensions
+	public static class ImageExtensions
 	{
 		public static Stretch ToStretch(this Aspect aspect)
 		{
@@ -26,11 +26,6 @@ namespace Xamarin.Forms.Platform.WPF
 			}
 		}
 
-		public static WImageSource ToWindowsImageSource(this ImageSource source)
-		{
-			return source.ToWindowsImageSourceAsync().GetAwaiter().GetResult();
-		}
-
 		public static async Task<WImageSource> ToWindowsImageSourceAsync(this ImageSource source, CancellationToken cancellationToken = default(CancellationToken))
 		{
 			if (source == null || source.IsEmpty)