Update knsrc to use kpackagetool5 commands
kwinswitcher.knsrc, kwinscripts.knsrc, kwineffect.knsrc
It seems the kwineffect.desktop was (and still is) invalid, as it
does not show up in kpackagetool5 --list-types.
To test, I overwrite the /etc/xdg/*.knsrc,
then opened the GHNS dialogs and installed stuff.
Differential Revision: https://phabricator.kde.org/D12249