Revert "Change default keyboard interactivity from exclusive to none"
This reverts commit be637838.
It broke keyboard input in sddm greeter. While defaulting to a non-spec value is not great, it's also not that critical. It might be worth considering synchronizing Qt::WindowDoesNotAcceptFocus with the keyboard interactivity flag, but the tricky part is that the keyboard interactivty is not just a boolean.