Missed calls should show a notification

Hi and thank you for maintaining plasma-mobile-dialer! Here using plasma-dialer 22.04-1 from jbb.ghsq.ga/debpm repository in Mobian bookworm on Pinephone 3GB.

Incoming calls that are not answered (lost calls) should raise a notification, for the user to call back in case of not hearing the call notification. Lost calls are correctly listed and flagged in the dialer history, but that requires user to check regularly. Lost call notification in the lockscreen would be the best solution. Otherwise, user does not even know someone tried to reach them.

As far as I can see with my poor programming skills, lost calls are not managed in kde-telephony-daemon/src/notification-manager.cpp. Only accepted and rejected calls seem to be handled.