The unit price set on output move is always in company currency
The unit price come from the cost price so it is always in company currency.
So when we set the unit price, we must force to also set the company currency as currency.
But as this can happen when we recompute the cost price, we must allow to modify the currency on done and closed period move like for unit_price. We must also set unit_price_updated
if the currency is changed.