fix tests

mobile/test/asset_grid_data_structure_test.dart

@@ -24,6 +24,7 @@ void main() {
         fileName: '',
         isFavorite: false,
         isArchived: false,
+        thumbhash: null,
       ),
     );
   }

mobile/test/sync_service_test.dart

@@ -34,6 +34,7 @@ void main() {
       fileName: localId ?? remoteId ?? "",
       isFavorite: false,
       isArchived: false,
+      thumbhash: null,
     );
   }