openapi gen return type fix for streaming/non-streaming

[yanxi0830]

What does this PR do?

We need to change

/v1/inference/chat-completion:
    post:
      responses:
        '200':
          description: >-
            If stream=False, returns a ChatCompletionResponse with the full completion.
            If stream=True, returns an SSE event stream of ChatCompletionResponseStreamChunk
          content:
            text/event-stream:
              schema:
                oneOf:
                  - $ref: '#/components/schemas/ChatCompletionResponse'
                  - $ref: '#/components/schemas/ChatCompletionResponseStreamChunk'

into

/v1/inference/chat-completion:
    post:
      responses:
        '200':
          description: >-
            If stream=False, returns a ChatCompletionResponse with the full completion.
            If stream=True, returns an SSE event stream of ChatCompletionResponseStreamChunk
          content:
            text/event-stream:
              schema:
                $ref: '#/components/schemas/ChatCompletionResponseStreamChunk'
            application/json:
              schema:
                $ref: '#/components/schemas/ChatCompletionResponse'

Test Plan

Python

• tested in SDK sync: Fix streaming/non-streaming return type differences llama-stack-client-python#108

Node

• tested w/ https://gist.github.com/yanxi0830/b782f4b91e21dcccdfef8898ce55157e (SDK udpate follow up)

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]

nice

[terrytangyuan]

LGTM. Should we run these SDK tests on a schedule?

[yanxi0830]

LGTM. Should we run these SDK tests on a schedule?

Not on schedule currently, but @sixianyi0721 added workflow that you can manually trigger by commit here: https://github.com/meta-llama/llama-stack/blob/main/.github/workflows/tests.yml