[C#] feat: add meeting handlers

[swatDong]

Linked issues

closes: #696

Details

Add handlers for meeting events

Change details

Add handlers under Application.Meetings for following events:

• application/vnd.microsoft.meetingStart
• application/vnd.microsoft.meetingEnd
• application/vnd.microsoft.meetingParticipantJoin
• application/vnd.microsoft.meetingParticipantLeave

Refactor InvokeActivityUtilities to ActivityUtilities since the event activity has Activity.Value as well.

Unit tests.

Attestation Checklist

• My code follows the style guidelines of this project

• I have checked for/fixed spelling, linting, and other errors

• I have commented my code for clarity

• I have made corresponding changes to the documentation (we use TypeDoc to document our code)

• My changes generate no new warnings

• I have added tests that validates my changes, and provides sufficient test coverage. I have tested with:

  • Local testing
  • E2E testing in Teams

• New and existing unit tests pass locally with my changes

Additional information

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