insufficient_quota in _exceptions.py

[akshit0201]

Confirm this is a feature request for the Python library and not the underlying OpenAI API.

• [X] This is a feature request for the Python library

Describe the feature or improvement you're requesting

Ratelimit error is not the only error related to code 429, insufficient funds is another one. Can we have another exception for this? Ratelimit is already handled internally by openai sdk, but insufficient funds needs to be handled externally by using a backup key.

Additional context

No response