[logout] It isn't obvious when the power button should be released when trying to get to the poweroff menu

Currently the poweroff menu appears when the power button is being released after holding it for some times. However, there is no indication when enough time has passed and you can release the button. This way you might hold the button till you're force shutting down the phone, which is unexpected.

Instead the menu should show when enough time has passed, no matter if the power button is still being held or not.