Ensure city dates in widget update correctly

Bug: 31026720

- Update widgets and day change callback whenever a TIME_SET occurs
  since that may have resulted in a day change for some cities.
- Account for home clock timezone when scheduling day change callback.

Test: Manually tested day change for MT home clock using SYD timezone.

Change-Id: I896aec59fe3b89de7ad4384c7987c7535296e164