Refa: migrate CV model chat to Async (#11828)

### What problem does this PR solve?

Migrate CV model chat to Async. #11750

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] Refactoring

rag/llm/chat_model.py

@@ -28,7 +28,7 @@ import json_repair
 import litellm
 import openai
 from openai import AsyncOpenAI, OpenAI
-from openai.lib.azure import AzureOpenAI
+from openai.lib.azure import AzureOpenAI, AsyncAzureOpenAI
 from strenum import StrEnum
 
 from common.token_utils import num_tokens_from_string, total_token_count_from_response
@@ -535,6 +535,7 @@ class AzureChat(Base):
         api_version = json.loads(key).get("api_version", "2024-02-01")
         super().__init__(key, model_name, base_url, **kwargs)
         self.client = AzureOpenAI(api_key=api_key, azure_endpoint=base_url, api_version=api_version)
+        self.async_client = AsyncAzureOpenAI(api_key=key, base_url=base_url, api_version=api_version)
         self.model_name = model_name
 
     @property