[Feat-Proxy-DataDog] Log Redis, Postgres Failure events on DataDog (#5750)

* dd - start tracking redis status on dd

* add async_service_succes_hook / failure hook in custom logger

* add async_service_failure_hook

* log service failures on dd

* fix import error

* add test for redis errors / warning

litellm/integrations/custom_logger.py

@@ -2,6 +2,7 @@
 #    On success, logs events to Promptlayer
 import os
 import traceback
+from datetime import datetime as datetimeObj
 from typing import Any, Literal, Optional, Tuple, Union
 
 import dotenv
@@ -10,6 +11,7 @@ from pydantic import BaseModel
 from litellm.caching import DualCache
 from litellm.proxy._types import UserAPIKeyAuth
 from litellm.types.llms.openai import ChatCompletionRequest
+from litellm.types.services import ServiceLoggerPayload
 from litellm.types.utils import AdapterCompletionStreamWrapper, ModelResponse