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

api/tasks/annotation/add_annotation_to_index_task.py

@@ -3,10 +3,8 @@ import time
 
 import click
 from celery import shared_task
-from langchain.schema import Document
-
 from core.index.index import IndexBuilder
-
+from langchain.schema import Document
 from models.dataset import Dataset
 from services.dataset_service import DatasetCollectionBindingService