When a revision is closed, always promote it out of draft

Summary:
Fixes T13300. Currently, if you create a revision and then immediately land it (either using --draft or just beating Harbormaster to the punch) it can be stuck in "Draft" forever.

Instead, count landing changes like this as a publishing action.

Test Plan:

• Used arc diff --hold to create a revision, then pushed the commit immediately.
• Before change: revision closed, but was stuck in draft.
• After change: revision closed and was promoted out of draft.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13300

Differential Revision: https://secure.phabricator.com/D20565