fixed Sarvam Integration and Typos (Fixes #19931)

[Nightwing-77]

Description

This PR fixes typos and incorrect references in the Sarvam AI integration in llama_index.

• Renames class from Servam to Sarvam
• Updates default model from "servam-m" to "sarvam-m"
• Updates API base from servam.ai to sarvam.ai
• Updates environment variable from SERVAM_API_KEY to SARVAM_API_KEY
• Fixes docstrings and package installation instructions

Fixes #19931

New Package?

• Yes
• No

Version Bump?

• Yes
• No

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

• I added/updated relevant unit tests (if applicable)
• I believe this change is already covered by existing unit tests

Suggested Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added Google Colab support for the newly added notebooks.
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I ran uv run make format; uv run make lint to appease the lint gods

[AstraBert]

Looks good, you need to change the details in the pyproject.toml of the integration to make this change effective tho (otherwise it will be still published under the old name)

[Nightwing-77]

Looks good, you need to change the details in the pyproject.toml of the integration to make this change effective tho (otherwise it will be still published under the old name)

Done, thanks!

[AstraBert]

Hey @Nightwing-77 there is a problem with the pyproject.toml, it seems to be invalid... When it is fixed, we can merge this :))

[Nightwing-77]

Hey @Nightwing-77 there is a problem with the pyproject.toml, it seems to be invalid... When it is fixed, we can merge this :))

i missed a comma 😭, my bad