UserInput Request/Response: rename id to requestId

[jozkee]

Id is too vague, changing to RequestId in both approval request/response contents. Related to https://github.com/dotnet/extensions/issues/6492

The naming of "id" parameters is confusing; it's not clear which ID they're referring to, and more than once I passed in the wrong ID. We should revisit the naming.

@westey-m

Microsoft Reviewers: Open in CodeFlow