Add note to gitlab_17_changes.md about 17.9 migration failure
What does this MR do and why?
This MR adds a note to doc/update/versions/gitlab_17_changes.md to warn users about a pitfall in upgrading to %17.9.
References
- #524402 (comment 2428902595)
- https://about.gitlab.com/releases/2025/03/26/patch-release-gitlab-17-10-1-released/
- !186236 (merged)
MR acceptance checklist
Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.
Edited by Pedro Pombeiro