[Feature flag - Cleanup] Remove `webauthn_without_totp` feature flag
`webauthn_without_totp` was rollout to all users of GitLab on the 9ht March 2023 (15.10). No complaints have been reported, so we assume we can remove the `webauthn_without_totp` feature flag.
## Owners
- Team: ~"group::authentication"
- Most appropriate slack channel to reach out to: `#g_manage_auth`
- Best individual to reach out to: @tachyons-gitlab @eduardosanz
- PM: @hsutor
## Stakeholders
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## Expectations
### What might happen if this goes wrong?
<!-- Any MRs that need to be rolled back? Communication that needs to happen? What are some things you can think of that could go wrong - data loss or broken pages? -->
### Cleaning up the feature flag
<!-- The checklist here is to help stakeholders keep track of the feature flag status -->
- [x] Create a merge request to remove `webauthn_without_totp` feature flag. Ask for review and merge it.
- [x] Remove all references to the feature flag from the codebase.
- [x] Remove the YAML definitions for the feature from the repository.
- [ ] Create [a changelog entry](https://docs.gitlab.com/ee/development/feature_flags/#changelog).
- [x] Ensure that the cleanup MR has been deployed to both production and canary.
If the merge request was deployed before [the code cutoff](https://about.gitlab.com/handbook/engineering/releases/#self-managed-releases-1),
the feature can be officially announced in a release blog post.
- [ ] `/chatops run auto_deploy status <merge-commit-of-cleanup-mr>`
- [x] Close [the feature issue](ISSUE LINK) to indicate the feature will be released in the current milestone.
- [x] If not already done, clean up the feature flag from all environments by running these chatops command in `#production` channel:
- [x] `/chatops run feature delete webauthn_without_totp --dev`
- [x] `/chatops run feature delete webauthn_without_totp --staging`
- [ ] `/chatops run feature delete webauthn_without_totp`
- [x] Close this rollout issue.
issue