Add OpenAIRealtimeExtensions with ToConversationFunctionTool

[SteveSandersonMS]

Realised this will involve upgrading the OpenAI library dependency from 2.0.0 to 2.1.0-beta.2.

I think the main things affected will be the Aspire.OpenAI and Aspire.Azure.AI.OpenAI packages, since they will then get a dependency on OpenAI 2.1.0-beta.2. Most likely that won't be a problem since they aren't going to be shipping with stable version numbers anyway (since they depend on M.E.AI) but @eerhardt / @sebastienros if you anticipate this being an issue, please let us know!

Testing

It's difficult to test this but I've done what I think is reasonable at present.

• For unit testing, we're constrainted by the fact that some of the realtime API types can't be instantiated or subclassed. So we can't actually create (for example) ConversationItemStreamingFinishedUpdate to use in a test.
• For integration testing, we're constrained by rate limits. It's only allowed to create one conversation session every 6 seconds. So for now there's only one integration test, and it combines a whole bunch of different behaviors to show the end-to-end is working.

If we go further with realtime API support in the future we'll need to find ways to test more, but hopefully this is sufficient coverage for now.

Microsoft Reviewers: Open in CodeFlow