Merge branch 'msj-deprecated-case' into 'master'

Format deprecated notices as lowercase

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/113398



Merged-by: Fiona Neill <fneill@gitlab.com>
Approved-by: Fiona Neill <fneill@gitlab.com>
Co-authored-by: Marcin Sedlak-Jakubowski <msedlakjakubowski@gitlab.com>