Merge branch 'private-email-regex-performance-fix' into 'master'

Cache private email regex for a request

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/144644



Merged-by: Doug Stull <dstull@gitlab.com>
Approved-by: Doug Stull <dstull@gitlab.com>
Approved-by: Gavin Hinfey <ghinfey@gitlab.com>
Co-authored-by: Robert May <rmay@gitlab.com>