Force expiration task to pick up any unexpired jobs that should have been expired rather than just jobs that should expire today [PD-691]

I've been unable to actually replicate this. My best theory is that the task failed on the day the job was actually set to expire, so it was never actually picked up for expiration. I've updated the task so that a job will expire the next time the task runs if for some reason it doesn't expire the exact day it's supposed to.

All tests pass.


I suspect that `datetime.date.today() - datetime.timedelta(1)` is clearer than adding a negative as you've done here. It's just a unit test, so I'm less worried about it.