[FR]: Optional extras for heavy dependencies in python SDK

Proposal summary

Having heavy dependencies like LiteLLM be optional.

Motivation

Using your python SDK, it comes with LiteLLM which is quite a heavy dependency, and I'm not using the LiteLLM integration what so ever. Without LiteLLM I can spin up my service with 4 workers for around 190MB. Simply using LiteLLM(even without Opik and its other dependencies), same setup runs at 700MB.