Unwrapping for "data"

[yanxi0830]

What does this PR do?

• add unwrap_response_fields: [data]

Test Plan

from llama_stack_client import LlamaStackClient
from rich.pretty import pprint

client = LlamaStackClient(base_url="http://localhost:5000")
pprint(client.models.list())

Sources

Please link relevant resources if necessary.

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• Ran pre-commit to handle lint / formatting issues.
• Read the contributor guideline,
  Pull Request section?
• Updated relevant documentation.
• Wrote necessary unit or integration tests.

[ashwinb]

yes yes yes yes yes yes

[ashwinb]

this level of OCD-ness is awesome!!!