Even if the next alarm is further in the future than the alarm on the
ScheduleCalendar, update the next alarm b/c this means that our current
nextAlarm is old info
Test: atest ScheduleCalendarTest
Test: manual
1. enable DND that ends at alarm
2. create an alarm that goes off in 5 min
3. change alarm to go off in 11 min
4. in the 6 minute difference, notice that DND is still on and didn't
end earlier than execpted.
Fixes: 181665547
Change-Id: Ieb2fc7269c4a9b1bc109941d16ce191012d338c4
8652e483b0