notifier: Only show the tray notifier on next notification time
This makes it follow the behaviour of the updates notification. It will only appear once per the timeframe specified in the KCM. It ignores the setting if there are urgent security updates to be applied, and shows the tray icon anyway.
Not sure if this actually fully addresses the bug as the wording is unclear, but FWIW the notification does follow the time set for me but the tray notifier doesn't, which I find annoying and is probably not expected behaviour.
Edited by Thomas Duckworth