Remove Action::Custom#inform_client once 12.3 has been released
Remove inform_client(info_message)
(and related code from https://gitlab.com/gitlab-org/gitlab-shell/blob/master/lib%2Faction%2Fcustom.rb#L27 once 12.3 has been released.
Related: !334 (merged) & gitlab!16584 (merged)
Edited by Ash McKenzie