fix(mobile): mobile album sort not persisting (#5584)

* chore(deps): use mocktail instead of mockito

* refactor: move stubs to fixtures/

* fix: fetch assetsortmode based on storeindex

* test: validate AlbumSortByOptions provider

---------

Co-authored-by: shenlong-tanwen <139912620+shalong-tanwen@users.noreply.github.com>

mobile/test/fixtures/user.stub.dart

@@ -0,0 +1,21 @@
+import 'package:immich_mobile/shared/models/user.dart';
+
+final class UserStub {
+  const UserStub._();
+
+  static final admin = User(
+    id: "admin",
+    updatedAt: DateTime(2021),
+    email: "admin@test.com",
+    name: "admin",
+    isAdmin: true,
+  );
+
+  static final user1 = User(
+    id: "user1",
+    updatedAt: DateTime(2022),
+    email: "user1@test.com",
+    name: "user1",
+    isAdmin: false,
+  );
+}