It is 3 working days.
But bear in mind that if your 3rd day is on a Thursday its realistically only 2.5 Days for obvious reasons. And if anyone screws up your leaving process there's nothing to be done after midday Thursday... I would opt to stay in Dubai for a further 3 days if you can before they book you out on the repatriation ticket.
Imagine if there's a dispute on the final paycheque amount?