The vacation edit sheet could save changes to an existing range but had
no way to remove it, forcing users back to the swipe-to-delete gesture
on the list. When editing (not creating) a range, the sheet now shows
an outlined delete action next to Save; it reuses the existing
confirmation dialog and EstadoAlarmas.eliminarRangoVacaciones exactly
as the swipe gesture already does, then pops on success.