Remove non-compliant Avatar sizes (Commits, deprecated notes)

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/166602



Merged-by: Alex Pennells <apennells@gitlab.com>
Approved-by: Chad Lavimoniere <clavimoniere@gitlab.com>
Approved-by: Doug Stull <dstull@gitlab.com>
Approved-by: Alex Pennells <apennells@gitlab.com>
Reviewed-by: Doug Stull <dstull@gitlab.com>
Reviewed-by: Sascha Eggenberger <seggenberger@gitlab.com>
Reviewed-by: Alex Pennells <apennells@gitlab.com>
Co-authored-by: Sascha Eggenberger <seggenberger@gitlab.com>