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.