Make task tests more reliable (partial fix, full in c0cb1d6)

Author: zhiltsov-max

tests/python/rest_api/test_tasks.py

@@ -3705,6 +3705,7 @@ def test_work_with_task_containing_non_stable_cloud_storage_files(
 
 
 @pytest.mark.usefixtures("restore_redis_inmem_per_function")
+@pytest.mark.usefixtures("restore_redis_ondisk_per_class")
 class TestTaskBackups:
     @pytest.fixture(autouse=True)
     def setup(
@@ -4306,6 +4307,7 @@ def test_task_unassigned_cannot_see_task_preview(
         self._test_assigned_users_cannot_see_task_preview(tasks, users, is_task_staff)
 
 
+@pytest.mark.usefixtures("restore_redis_ondisk_per_class")
 class TestUnequalJobs:
     @pytest.fixture(autouse=True)
     def setup(self, restore_db_per_function, tmp_path: Path, admin_user: str):