Rollout: auto_assign_code_owner_reviewers feature flag

Summary

Feature flag rollout issue for auto_assign_code_owner_reviewers.

This feature flag gates the automatic assignment of CODEOWNERS as reviewers on merge requests.

Feature flag

• Name: auto_assign_code_owner_reviewers
• Type: gitlab_com_derisk
• Default: false
• Group: group::code review

Related

• Epic: &20708
• Design issue: #589700
• Implementation MR: !223240 (closed)

Rollout plan

• Enable on staging
• Enable on gitlab.com for a subset of projects
• Monitor for errors/performance issues
• Enable on gitlab.com globally
• Remove feature flag and clean up