Remove unnecessary check

_loadedFinalImage will be true only after _loadedSmallThumbnail becomes true as first the small thumbnail is loaded and then the final image

mobile/lib/ui/viewer/file/zoomable_image.dart

@@ -129,7 +129,7 @@ class _ZoomableImageState extends State<ZoomableImage>
   }
 
   void _loadNetworkImage() {
-    if (!_loadedSmallThumbnail && !_loadedFinalImage) {
+    if (!_loadedSmallThumbnail) {
       final cachedThumbnail = ThumbnailInMemoryLruCache.get(_photo);
       if (cachedThumbnail != null) {
         _imageProvider = Image.memory(cachedThumbnail).image;