Bump external/usersim from 88a336d to d91240e (#3994)

Bumps [external/usersim](https://github.com/microsoft/usersim) from `88a336d` to `d91240e`.
- [Commits](microsoft/usersim@88a336d...d91240e)

---
updated-dependencies:
- dependency-name: external/usersim
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Sharmi <[email protected]>