Make draft toggle idempotent
A community contributor proposed making `/draft` idempotent (https://gitlab.com/gitlab-org/gitlab/-/merge_requests/89874) which will require a few separate steps
1. Add ~backend support for `ready` and a temporary idempotent `draft` method - we may not use this new draft method right away, but since it's a simple reverse, we should implement it at the same time
1. Add `/ready` as a quick-action
1. Reroute ~frontend, API, etc events to use the new idempotent actions
1. Confirm any side-effects or implicit expectations around toggling `draft` status on the DB record
1. Cleanup - migrate the idempotent `draft` method and remove the old code
Some brainstorming and discussion in thread https://gitlab.com/gitlab-org/gitlab/-/merge_requests/89874#note_992757722
issue