fix pylint issue

Author: Pavan-Microsoft

src/api/app.py

@@ -14,7 +14,6 @@
 from dotenv import load_dotenv
 import uvicorn
 
-from common.config.config import Config
 from agents.agent_factory import AgentFactory
 from api.api_routes import router as backend_router
 from api.history_routes import router as history_router