[Backend] Maybe go back to previous embedding function

[apirrone]

Did it run locally ?

With openai embeddings you could get :

Retrying langchain.embeddings.openai.embed_with_retry.<locals>._embed_with_retry in 4.0 seconds as it raised 
APIConnectionError: Error communicating with OpenAI: HTTPSConnectionPool(host='api.openai.com', port=443): Max retries 
exceeded with url: /v1/embeddings (Caused by NameResolutionError("<urllib3.connection.HTTPSConnection object at 
0x7f8289f978b0>: Failed to resolve 'api.openai.com' ([Errno -3] Temporary failure in name resolution)")).