Merge branch '498277-drop-runners-registration-token' into 'master'

Remove runners registration token from application settings

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/169033



Merged-by: Pavel Shutsin <pshutsin@gitlab.com>
Approved-by: Pavel Shutsin <pshutsin@gitlab.com>
Approved-by: Rémy Coutable <remy@rymai.me>
Reviewed-by: Rémy Coutable <remy@rymai.me>
Reviewed-by: Pavel Shutsin <pshutsin@gitlab.com>
Co-authored-by: Rutvik Chandla <rutvik.c@browserstack.com>