What does this MR do?
Backport ability to enable/disable file attachments in issuable form (https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/3434)
Are there points in the code the reviewer needs to double check?
Why was this MR needed?
Makes CE => EE less painful
Screenshots (if relevant)
Does this MR meet the acceptance criteria?
Tests added for this feature/bug
Has been reviewed by Frontend