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

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

api/tasks/enable_segments_to_index_task.py

@@ -1,4 +1,3 @@
-import datetime
 import logging
 import time
 
@@ -10,6 +9,7 @@ from core.rag.index_processor.index_processor_factory import IndexProcessorFacto
 from core.rag.models.document import ChildDocument, Document
 from extensions.ext_database import db
 from extensions.ext_redis import redis_client
+from libs.datetime_utils import naive_utc_now
 from models.dataset import Dataset, DocumentSegment
 from models.dataset import Document as DatasetDocument
 
@@ -103,7 +103,7 @@ def enable_segments_to_index_task(segment_ids: list, dataset_id: str, document_i
             {
                 "error": str(e),
                 "status": "error",
-                "disabled_at": datetime.datetime.now(datetime.UTC).replace(tzinfo=None),
+                "disabled_at": naive_utc_now(),
                 "enabled": False,
             }
         )