refactor: Remove unused import and simplify post_code_processing method

src/backend/base/langflow/api/utils.py

@@ -1,10 +1,8 @@
 import uuid
 import warnings
-from pathlib import Path
 from typing import TYPE_CHECKING, Optional
 
 from fastapi import HTTPException
-from platformdirs import user_cache_dir
 from sqlmodel import Session
 
 from langflow.graph.graph.base import Graph