test: fix flake8 unused imports

backend/tests/test_mission_control_approval_check.py

@@ -4,7 +4,7 @@ from uuid import uuid4
 
 import pytest
 from sqlalchemy.ext.asyncio import AsyncEngine, create_async_engine
-from sqlmodel import SQLModel, col, select
+from sqlmodel import SQLModel
 from sqlmodel.ext.asyncio.session import AsyncSession
 
 from app.models.approval_task_links import ApprovalTaskLink