Merge branch 'dg-sort-assignees' into 'master'

Sort work item assignees on frontend by name

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/142519



Merged-by: Simon Knox <simon@gitlab.com>
Approved-by: Nick Leonard <nleonard@gitlab.com>
Approved-by: Simon Knox <simon@gitlab.com>
Reviewed-by: Simon Knox <simon@gitlab.com>
Reviewed-by: Nick Leonard <nleonard@gitlab.com>
Co-authored-by: Deepika Guliani <dguliani@gitlab.com>