We set url to the job name if it's missing, but a job name is not a url
nor is it additional information. Then, in dashboard displays
we have display code that sets url to null if it matches the job name.
Instead of fixing the data at the display layer, let's set it to null in
the first place. So that we can update the dashboard code to remove the
workarounds, let's also run a migration to update the previously saved