Merge branch '421683_fix_500_for_x509_commits' into 'master'

Fix 500 error for X509 commits without a certificate

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/138521



Merged-by: Hordur Freyr Yngvason <hfyngvason@gitlab.com>
Approved-by: Gavin Hinfey <ghinfey@gitlab.com>
Approved-by: Hordur Freyr Yngvason <hfyngvason@gitlab.com>
Reviewed-by: Vasilii Iakliushin <viakliushin@gitlab.com>
Co-authored-by: Vasilii Iakliushin <viakliushin@gitlab.com>