Migrate to V2 Pydantic interface

[emmanuel-ferdman]

What does this PR do?

This PR updates Pydantic V1 Model.schema() calls to the Pydantic V2 equivalent Model.model_json_schema() to resolve PydanticDeprecatedSince20 warnings.

Changes Made:

• Replaced Animals.schema() with Animals.model_json_schema() in docs/source/basic_tutorials/using_guidance.md.
• Replaced multiple instances of Weather.schema() with Weather.model_json_schema() in integration-tests/models/test_grammar_response_format_llama.py.

These changes ensure compatibility with Pydantic V2+ and address deprecation warnings related to the Model.schema() method, as observed in CI logs.

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• Did you read the contributor guideline,
  Pull Request section?
• Was this discussed/approved via a Github issue or the forum? Please add a link
  to it if that's the case.
• Did you make sure to update the documentation with your changes? Here are the
  documentation guidelines, and
  here are tips on formatting docstrings.
• Did you write any new necessary tests?

Who can review?

Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
members/contributors who may be interested in your PR.

[emmanuel-ferdman]

@regisss @Narsil could you please review this small PR when you get the chance? thank you 🙌