[C#] chore: Remove questbot (#962)

## Linked issues

closes: #959  (issue number)

## Details

- Remove quest bot since it's not ready for the next release. In the
future we can decide to add it back by finding it in the commit history.

## Attestation Checklist

- [x] 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](https://typedoc.org/) 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