KStatusNotifierItem: use actions instead of Yes/No in Quit confirm dialog
Yes/No button texts are usually discouraged, also by KDE HIG:
Buttons should clearly indicate the available options using action verbs (“Delete”, “Rename”, “Close”, “Accept”, etc.) and allow the user to make an informed decision even if they have not read the message text. Never use “Yes” and “No” as button titles.
See https://develop.kde.org/hig/components/assistance/message/#appearance
Tested with Konversation's usage of KStatusNotifierItem.