[Chore/Refactor] Use centralized naive_utc_now for UTC datetime operations (#24352)

Signed-off-by: -LAN- <laipz8200@outlook.com>

api/tasks/duplicate_document_indexing_task.py

@@ -1,4 +1,3 @@
-import datetime
 import logging
 import time
 
@@ -9,6 +8,7 @@ from configs import dify_config
 from core.indexing_runner import DocumentIsPausedError, IndexingRunner
 from core.rag.index_processor.index_processor_factory import IndexProcessorFactory
 from extensions.ext_database import db
+from libs.datetime_utils import naive_utc_now
 from models.dataset import Dataset, Document, DocumentSegment
 from services.feature_service import FeatureService
 
@@ -55,7 +55,7 @@ def duplicate_document_indexing_task(dataset_id: str, document_ids: list):
             if document:
                 document.indexing_status = "error"
                 document.error = str(e)
-                document.stopped_at = datetime.datetime.now(datetime.UTC).replace(tzinfo=None)
+                document.stopped_at = naive_utc_now()
                 db.session.add(document)
         db.session.commit()
         return
@@ -86,7 +86,7 @@ def duplicate_document_indexing_task(dataset_id: str, document_ids: list):
                 db.session.commit()
 
             document.indexing_status = "parsing"
-            document.processing_started_at = datetime.datetime.now(datetime.UTC).replace(tzinfo=None)
+            document.processing_started_at = naive_utc_now()
             documents.append(document)
             db.session.add(document)
     db.session.commit()