R1:d8834377be0c

When a Herald rule blocks a push, show which rule fired in the push log UI

Summary:
Ref T13164. See PHI765. We currently show "Rejected: Herald" in the push log UI, but don't show which rule rejected a push.

We store this data, and it's potentially useful: either for hunting down a particular issue, or for getting a general sense of how often a reject rule is triggering (maybe because you want to tune how aggressive it is).

Show this data in the web UI, and include it in the data export payload.

Test…