R1:d6afce7d3097

Stop "join project" from trying to write an inverse edge on Users

Summary: Now that Users implement PhabricatorApplicationTransactionInterface, we try to write an inverse edge. At least for now, we should retain the old behavior instead.

Test Plan:
- Unit tests which cover this stuff pass again.
- Grepped for other `instanceof PhabricatorApplicationTransactionInterface`, the all seemed either benign or irrelevant.

Reviewers: joshuaspence, btrahan

Reviewed By: btrahan

Subscribers: epriestley…