Merge branch 'fix-merged-by' into 'master'

Add merge and closed user ids to MR metrics

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/157206



Merged-by: Rodrigo Tomonari <rtomonari@gitlab.com>
Approved-by: Rodrigo Tomonari <rtomonari@gitlab.com>
Co-authored-by: Luke Duncalfe <lduncalfe@eml.cc>
Co-authored-by: carlad-gl <cdrago@gitlab.com>