When a Worker would sign off while working on a task, and that task's
job would be in `pause-requested` state, it would always re-queue the
task. This in turn would not get detected, which caused the job to get
stuck.
Now tasks correctly go to `paused` when a Worker signs off, and
subsequently the job will be re-checked and go to `paused` when possible
as well.
Note that this does not handle already-stuck jobs. That'll be for the
following commit.
ff29d2ef26