community: Add deprecation notice for Databricks integration in langchain-community (#27355)

We have released the
[langchain-databricks](https://github.com/langchain-ai/langchain-databricks)
package for Databricks integration. This PR deprecates the legacy
classes within `langchain-community`.

---------

Signed-off-by: B-Step62 <yuki.watanabe@databricks.com>
Co-authored-by: Erick Friis <erick@langchain.dev>

libs/community/langchain_community/llms/databricks.py

@@ -5,6 +5,7 @@ from abc import ABC, abstractmethod
 from typing import Any, Callable, Dict, List, Mapping, Optional
 
 import requests
+from langchain_core._api import deprecated
 from langchain_core.callbacks import CallbackManagerForLLMRun
 from langchain_core.language_models import LLM
 from pydantic import (
@@ -262,6 +263,11 @@ def _pickle_fn_to_hex_string(fn: Callable) -> str:
         raise ValueError(f"Failed to pickle the function: {e}")
 
 
+@deprecated(
+    since="0.3.3",
+    removal="1.0",
+    alternative_import="langchain_databricks.ChatDatabricks",
+)
 class Databricks(LLM):
     """Databricks serving endpoint or a cluster driver proxy app for LLM.