feat: [backend] vision support (#1510)

Co-authored-by: Garfield Dai <dai.hai@foxmail.com>

api/core/model_providers/models/llm/openai_model.py

@@ -1,11 +1,9 @@
-import decimal
 import logging
 from typing import List, Optional, Any
 
 import openai
 from langchain.callbacks.manager import Callbacks
 from langchain.schema import LLMResult
-from openai import api_requestor
 
 from core.model_providers.providers.base import BaseModelProvider
 from core.third_party.langchain.llms.chat_open_ai import EnhanceChatOpenAI