feat(tools): add response_scheduling to control Live function response behavior

[allen-stephen]

Please ensure you have read the contribution guide before creating a pull request.

Link to Issue or Description of Change

Adds support for Live API function response scheduling (https://docs.cloud.google.com/gemini-enterprise-agent-platform/models/live-api/asynchronous-function-calling)

Testing Plan

Unit Tests:

• I have added or updated unit tests for my change.
• All unit tests pass locally.

tests/unittests/tools/ tests/unittests/flows/llm_flows/ -> 438 passed

Manual End-to-End (E2E) Tests:

Set tool.response_scheduling = types.FunctionResponseScheduling.SILENT on a tool in a Live agent and confirmed the model updates state without narrating the tool result; with None (default), behavior is unchanged.

Checklist

• I have read the CONTRIBUTING.md document.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• 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 have manually tested my changes end-to-end.
• Any dependent changes have been merged and published in downstream modules.

[rohityan]

Hi @allen-stephen , Thank you for your contribution! We appreciate you taking the time to submit this pull request. Your PR has been received by the team and is currently under review. We will provide feedback as soon as we have an update to share.

[rohityan]

Hi @xuanyang15 , can you please review this.