Automatically rescheduled issues to 12.4

The following were rescheduled because the previous milestone was already closed:

1. #11058 (closed) Improve UX for multiple assignees in merge requests Deliverable, Enterprise Edition, ~"UX ready", backend, devopscreate, frontend, groupsource code, merge requests, missed-deliverable, workflowverification
2. #26466 (closed) GitLab importing repositories from GitHub shouldn't result in 500 error ~"P2", ~"S2", backend, ~"bug", customer, devopsmanage, gitlab.com, ~"group::import", ~"import", ~"missed-SLO", movingtogitlab, project, reproduced on GitLab.com

Please reschedule accordingly if they're wrong.