[Frontend][Responses API] Function call streaming

[madskildegaard]

Adding streaming support for function calling in Responses API.

Refer to OpenAI responses function calling docs

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[madskildegaard]

@chaunceyjiang Hey, I used your branch and found out I needed streaming support for function calls, so I tried implementing it on top of your branch.

Feel free to take a look and suggest changes if you want.

[chaunceyjiang]

Thank you, @madskildegaard, for your excellent work!

[github-actions]

This pull request has been automatically marked as stale because it has not had any activity within 90 days. It will be automatically closed if no further activity occurs within 30 days. Leave a comment if you feel this pull request should remain open. Thank you!

[github-actions]

This pull request has been automatically closed due to inactivity. Please feel free to reopen if you intend to continue working on it. Thank you!