Fixed Android's StreamImageSourceService.LoadDrawableAsync()

Transition back to the calling thread context (which should theoretically be the main thread).

Fixes issue #14052

src/Core/src/ImageSources/StreamImageSourceService/StreamImageSourceService.Android.cs

@@ -21,7 +21,7 @@ public partial class StreamImageSourceService
 				Stream? stream = null;
 				try
 				{
-					stream = await streamImageSource.GetStreamAsync(cancellationToken).ConfigureAwait(false);
+					stream = await streamImageSource.GetStreamAsync(cancellationToken);
 
 					var callback = new ImageLoaderCallback();