Add hideCalendarNotes support to reschedule flow
The hideCalendarNotes flag was only handled in CalendarManager.createEvent(), not in updateEvent(). This caused notes to become visible again in ICS files after rescheduling.
Changes:
- Add hideCalendarNotes handling to CalendarManager.updateEvent()
- Add hideCalendarNotes checks to reschedule email functions
- Move description reset before reschedule call (required for cloned event)
