Bump external/usersim from 5f70910 to ef585ae (#46)

Bumps [external/usersim](https://github.com/microsoft/usersim) from `5f70910` to `ef585ae`.
- [Commits](microsoft/usersim@5f70910...ef585ae)

---
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>