[Notifications] When application responds to cancel request, stop kill timer
This ensures that an error message the app might have sent in response to the cancel request is still shown.
Also, while at it deduplicate code by calling into terminate from the
service watcher.
- stopped a job that returned an error: got the error shown now. previously the popup would still disappear after two seconds
- started a copy,
SIGSTOPdolphin, canceled the job, waited, popup would still go away - started a copy,
SIGSTOPdolphin, canceled the job,SIGKILLdolphin, "app closed unexpectedly" would be shown, previously it would just disappear