[11.1] TimePage: improve behavior if Location access isn't granted

@ChenYiLins implemented the warning that shows if Auto Dark Mode doesn't have location access. The behaviour of Auto Dark Mode in this state is still a bit weird. I would say: just try it out on your system, click around, test some scenarios and you will know what I mean. Just improve the overall Location access isn't granted experience. Maybe Auto Dark Mode should switch back to Custom Time for example.