* Fix duplicate permission checks for same user
Deduplicate user list in checkUserListPermissions before running expensive checks.
Handles ObjectId vs string comparison by converting to string.
Adds tests to verify deduplication works correctly.
---------
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: thomas- <2176518+thomas-@users.noreply.github.com>
GitOrigin-RevId: 96eede1cbeb18b807deaca7d4c370aef5c48c4bc