Messenger::unregisterCalendar

static function unregisterCalendar(int $eventId, array $entry): void
{
	if ($entry['ID'] !== $entry['PARENT_ID'])
	{
		return;
	}

	$calendarService = new CalendarService();
	$calendar = CalendarItem::getByCalendarId($eventId, false);
	if ($calendar === null)
	{
		return;
	}
	$calendarService->unregisterCalendar($calendar);
}