feat(databricks/chat): support structured outputs on databricks

Closes https://github.com/BerriAI/litellm/pull/6978

- handles content as list for dbrx, - handles streaming+response_format for dbrx

litellm/llms/databricks/chat/handler.py

@@ -0,0 +1,82 @@
+"""
+Handles the chat completion request for Databricks
+"""
+
+from typing import Any, Callable, Literal, Optional, Tuple, Union
+
+from httpx._config import Timeout
+
+from litellm.llms.custom_httpx.http_handler import AsyncHTTPHandler, HTTPHandler
+from litellm.types.utils import CustomStreamingDecoder
+from litellm.utils import ModelResponse
+
+from ...openai_like.chat.handler import OpenAILikeChatHandler
+from ..common_utils import DatabricksBase
+from ..exceptions import DatabricksError
+from .transformation import DatabricksConfig
+
+
+class DatabricksChatCompletion(OpenAILikeChatHandler, DatabricksBase):
+    def __init__(self, **kwargs):
+        super().__init__(**kwargs)
+
+    def completion(
+        self,
+        *,
+        model: str,
+        messages: list,
+        api_base: str,
+        custom_llm_provider: str,
+        custom_prompt_dict: dict,
+        model_response: ModelResponse,
+        print_verbose: Callable,
+        encoding,
+        api_key: Optional[str],
+        logging_obj,
+        optional_params: dict,
+        acompletion=None,
+        litellm_params=None,
+        logger_fn=None,
+        headers: Optional[dict] = None,
+        timeout: Optional[Union[float, Timeout]] = None,
+        client: Optional[Union[HTTPHandler, AsyncHTTPHandler]] = None,
+        custom_endpoint: Optional[bool] = None,
+        streaming_decoder: Optional[CustomStreamingDecoder] = None,
+        fake_stream: bool = False,
+    ):
+        messages = DatabricksConfig()._transform_messages(messages)  # type: ignore
+        api_base, headers = self.databricks_validate_environment(
+            api_base=api_base,
+            api_key=api_key,
+            endpoint_type="chat_completions",
+            custom_endpoint=custom_endpoint,
+            headers=headers,
+        )
+
+        if optional_params.get("stream") is True:
+            fake_stream = DatabricksConfig()._should_fake_stream(optional_params)
+        else:
+            fake_stream = False
+
+        return super().completion(
+            model=model,
+            messages=messages,
+            api_base=api_base,
+            custom_llm_provider=custom_llm_provider,
+            custom_prompt_dict=custom_prompt_dict,
+            model_response=model_response,
+            print_verbose=print_verbose,
+            encoding=encoding,
+            api_key=api_key,
+            logging_obj=logging_obj,
+            optional_params=optional_params,
+            acompletion=acompletion,
+            litellm_params=litellm_params,
+            logger_fn=logger_fn,
+            headers=headers,
+            timeout=timeout,
+            client=client,
+            custom_endpoint=True,
+            streaming_decoder=streaming_decoder,
+            fake_stream=fake_stream,
+        )