chore: Avoid directly using OpenAI dependencies (#26590)

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

api/services/app_generate_service.py

@@ -2,8 +2,6 @@ import uuid
 from collections.abc import Generator, Mapping
 from typing import Any, Union
 
-from openai._exceptions import RateLimitError
-
 from configs import dify_config
 from core.app.apps.advanced_chat.app_generator import AdvancedChatAppGenerator
 from core.app.apps.agent_chat.app_generator import AgentChatAppGenerator
@@ -122,8 +120,6 @@ class AppGenerateService:
                 )
             else:
                 raise ValueError(f"Invalid app mode {app_model.mode}")
-        except RateLimitError as e:
-            raise InvokeRateLimitError(str(e))
         except Exception:
             rate_limit.exit(request_id)
             raise