[Android] Fix: Prevent Duplicate MapSource Invocations on setting Image's Source to Local File Paths (#28405)

* add extra condition

* use _sourceCancellation

Author: bhavanesh2001

src/Core/src/Handlers/Image/ImageHandler.Android.cs

@@ -100,7 +100,7 @@ internal static void OnPlatformViewAttachedToWindow(IImageHandler imageHandler)
 			// So we want to reload the image here if it's supposed to have an image
 			if (imageHandler.SourceLoader.CheckForImageLoadedOnAttached &&
 				imageHandler.PlatformView.Drawable is null &&
-				imageHandler.VirtualView.Source is not null)
+				imageHandler.VirtualView.Source is not null && !imageHandler.SourceLoader.SourceManager.IsLoading)
 			{
 				imageHandler.SourceLoader.CheckForImageLoadedOnAttached = false;
 				imageHandler.UpdateValue(nameof(IImage.Source));

src/Core/src/ImageSources/ImageSourceServiceResultManager.cs

@@ -26,6 +26,7 @@ internal class ImageSourceServiceResultManager
 		CancellationTokenSource? _sourceCancellation;
 		IDisposable? _sourceResult;
 
+		public bool IsLoading => _sourceCancellation is not null;
 		public CancellationToken Token =>
 			_sourceCancellation?.Token ?? default;