fix: improve maintenance and synchronize live conversations

backend/app/repositories/notification_settings.py

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 """
 
-from typing import Iterable, List, Optional, Set
+from typing import Iterable, Optional, Set
 from uuid import UUID
 
 from sqlalchemy.exc import IntegrityError