Bump external/usersim from 88a336d to d91240e in the actions group

Bumps the actions group with 1 update: [external/usersim](https://github.com/microsoft/usersim).


Updates `external/usersim` from `88a336d` to `d91240e`
- [Commits](microsoft/usersim@88a336d...d91240e)

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

Signed-off-by: dependabot[bot] <[email protected]>