Fix shimmer background width for grid mode

Signed-off-by: Abdourahamane Boinaidi <abdourahamane.boinaidi@infomaniak.com>

src/main/java/com/owncloud/android/ui/adapter/OCFileListAdapter.java

@@ -737,7 +737,7 @@ public class OCFileListAdapter extends RecyclerView.Adapter<RecyclerView.ViewHol
 
     private static void configShimmerGridImageSize(ImageView shimmerThumbnail, int size){
         shimmerThumbnail.setImageResource(R.drawable.background);
-        FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(size,size);
+        FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(FrameLayout.LayoutParams.MATCH_PARENT,size);
         shimmerThumbnail.setLayoutParams(params);
     }