When editing a scheduler job, call setDirty when target is selected from the pop-up list.
The target and RA/DEC boxes were only triggering the job update when editing the text and leaving the field.
When the pop-up list was used, the programmatic update of those fields wasn't triggering that update.

This fixes the use case where the end-user is looking for a target to start in ASAP mode.
In that use case, the end-user will select targets and observe the starting date/time the Scheduler computed.

Create a Scheduler job.
Click its line in the job table once to edit it, and click the search button.
Choose another target, the target and RA/DEC fields reflect the update.
Click the add/save-job button.
Prior to this fix, the job would not be updated in the queue table.
With this fix, the job is properly updated.