fix: timezone not imported in conversation service. (#11076)

api/services/conversation_service.py

+from collections.abc import Callable
 from datetime import UTC, datetime
 from typing import Optional, Union
 
         return InfiniteScrollPagination(data=conversations, limit=limit, has_more=has_more)
 
     @classmethod
-    def _get_sort_params(cls, sort_by: str) -> tuple[str, callable]:
+    def _get_sort_params(cls, sort_by: str):
         if sort_by.startswith("-"):
             return sort_by[1:], desc
         return sort_by, asc
 
     @classmethod
     def _build_filter_condition(
-        cls, sort_field: str, sort_direction: callable, reference_conversation: Conversation, is_next_page: bool = False
+        cls, sort_field: str, sort_direction: Callable, reference_conversation: Conversation, is_next_page: bool = False
     ):
         field_value = getattr(reference_conversation, sort_field)
         if (sort_direction == desc and not is_next_page) or (sort_direction == asc and is_next_page):
         conversation = cls.get_conversation(app_model, conversation_id, user)
 
         conversation.is_deleted = True
-        conversation.updated_at = datetime.now(timezone.utc).replace(tzinfo=None)
+        conversation.updated_at = datetime.now(UTC).replace(tzinfo=None)
         db.session.commit()