After this sequence of events:
- You create a revision associated with an arcanist project.
- The arcanist project is associated with a repository.
- You manually edit the revision to remove the `repositoryPHID`.
- Herald rules trigger.
...Herald will too ambitiously re-resolve the arcanist project and come up with a nonempty `repositoryPHID`. This was the correct rule before, but no longer is. This resolution should be happening in Differential and Herald should just trust Differential.