Add gemini/gemini-pro model to fetched models

[AbhisekOmkar]

This commit adds the gemini/gemini-pro model to the list of models fetched from the server in the fetchModels function.

[foragerr]

This issue is already fixed. See this: https://github.com/OpenDevin/OpenDevin/issues/591#issuecomment-2034662809

Moreover hardcoding model ids in OpenDevin is a bad idea, could cause divergence from what is actually supported in Litellm.

[rbren]

Closing thanks to the alternate fix