improve: introduce isort for linting Python imports (#1983)

api/core/data_loader/loader/pdf.py

@@ -1,11 +1,10 @@
 import logging
 from typing import List, Optional
 
+from extensions.ext_storage import storage
 from langchain.document_loaders import PyPDFium2Loader
 from langchain.document_loaders.base import BaseLoader
 from langchain.schema import Document
-
-from extensions.ext_storage import storage
 from models.model import UploadFile
 
 logger = logging.getLogger(__name__)