Update distributed group chat example to use streaming API calls as well

[MohMaz]

Why are these changes needed?

Making distributed group chat example include a streaming API integration with the UI

Related issue number

Checks

• [x] I've included any doc changes needed for https://microsoft.github.io/autogen/. See https://microsoft.github.io/autogen/docs/Contribute#documentation to build and test documentation locally.
• [x] I've added tests (if relevant) corresponding to the changes introduced in this PR.
• [x] I've made sure all auto checks have passed.

[MohMaz]

@ekzhu can you please review when you got a chance?

[jackgerrits]

@victordibia FYI

[ekzhu]

@MohMaz @jackgerrits this PR is a bit stall. Shall we first fix the ChatCompletionClient protocol to add the * to fix the client argument list.

[MohMaz]

Closing this PR. Will open separate PRs to address to fix the protocol and then add the streaming again.