chore(mobile): Favorite provider unit test (#1874)

* Favorite provider tests

* Remove unused mock

* Add setUp function to avoid duplicate code

mobile/lib/modules/favorite/providers/favorite_provider.dart

@@ -3,14 +3,15 @@ import 'package:immich_mobile/shared/models/asset.dart';
 import 'package:immich_mobile/shared/providers/asset.provider.dart';
 
 class FavoriteSelectionNotifier extends StateNotifier<Set<String>> {
-  FavoriteSelectionNotifier(this.ref) : super({}) {
-    state = ref.watch(assetProvider).allAssets
+  FavoriteSelectionNotifier(this.assetsState, this.assetNotifier) : super({}) {
+    state = assetsState.allAssets
         .where((asset) => asset.isFavorite)
         .map((asset) => asset.id)
         .toSet();
   }
 
-  final Ref ref;
+  final AssetsState assetsState;
+  final AssetNotifier assetNotifier;
 
   void _setFavoriteForAssetId(String id, bool favorite) {
     if (!favorite) {
@@ -29,7 +30,7 @@ class FavoriteSelectionNotifier extends StateNotifier<Set<String>> {
 
     _setFavoriteForAssetId(asset.id, !_isFavorite(asset.id));
 
-    await ref.watch(assetProvider.notifier).toggleFavorite(
+    await assetNotifier.toggleFavorite(
       asset,
       state.contains(asset.id),
     );
@@ -37,8 +38,8 @@ class FavoriteSelectionNotifier extends StateNotifier<Set<String>> {
 
   Future<void> addToFavorites(Iterable<Asset> assets) {
     state = state.union(assets.map((a) => a.id).toSet());
-    final futures = assets.map((a) => 
-        ref.watch(assetProvider.notifier).toggleFavorite(
+    final futures = assets.map((a) =>
+        assetNotifier.toggleFavorite(
           a,
           true,
         ),
@@ -50,7 +51,10 @@ class FavoriteSelectionNotifier extends StateNotifier<Set<String>> {
 
 final favoriteProvider =
     StateNotifierProvider<FavoriteSelectionNotifier, Set<String>>((ref) {
-  return FavoriteSelectionNotifier(ref);
+  return FavoriteSelectionNotifier(
+      ref.watch(assetProvider),
+      ref.watch(assetProvider.notifier),
+  );
 });
 
 final favoriteAssetProvider = StateProvider((ref) {