fixes image retention when no network is available (commons-app#5335)

Author: srishti-R

app/src/main/java/fr/free/nrw/commons/media/MediaDetailFragment.java

@@ -604,11 +604,12 @@ private void setupImageView() {
         image.getHierarchy().setFailureImage(R.drawable.image_placeholder);
 
         DraweeController controller = Fresco.newDraweeControllerBuilder()
-                .setLowResImageRequest(ImageRequest.fromUri(media != null ? media.getThumbUrl() : null))
-                .setImageRequest(ImageRequest.fromUri(media != null ? media.getImageUrl() : null))
-                .setControllerListener(aspectRatioListener)
-                .setOldController(image.getController())
-                .build();
+            .setLowResImageRequest(ImageRequest.fromUri(media != null ? media.getThumbUrl() : null))
+            .setRetainImageOnFailure(true)
+            .setImageRequest(ImageRequest.fromUri(media != null ? media.getImageUrl() : null))
+            .setControllerListener(aspectRatioListener)
+            .setOldController(image.getController())
+            .build();
         image.setController(controller);
     }