OAI: Allow /v1/encode endpoint to handle vision requests

* More robust checks for OAI chat completion message lists on /v1/encode endpoint
* Added TODO to support other aspects of chat completions
* Fix oversight where embeddings was not defined in advance on /v1/chat/completions endpoint

endpoints/OAI/router.py

@@ -1,4 +1,5 @@
 import asyncio
+from common.multimodal import MultimodalEmbeddingWrapper
 from fastapi import APIRouter, Depends, HTTPException, Request
 from sse_starlette import EventSourceResponse
 from sys import maxsize
@@ -124,6 +125,8 @@ async def chat_completion_request(
 
     model_path = model.container.model_dir
 
+    embeddings = MultimodalEmbeddingWrapper()
+
     if isinstance(data.messages, str):
         prompt = data.messages
     else: