chore(deps): update dependency registry1.dso.mil/ironbank/opensource/mattermost/mattermost to v9.1.1

This MR contains the following updates:

Package	Update	Change
registry1.dso.mil/ironbank/opensource/mattermost/mattermost	patch	9.1.0 -> 9.1.1

---

Configuration

📅 Schedule: At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Renovate will not automatically rebase this PR, because other commits have been found.

🔕 Ignore: Close this MR and you won't be reminded about this update again.

---

• If you want to rebase/retry this MR, click this checkbox.

---

This MR has been generated by Renovate Bot.