Bug 33783: (bug 8179 follow-up) Populate actual cost with ecost during receiving...

Bug 33783: (bug 8179 follow-up) Populate actual cost with ecost during receiving if not set

This restores behavior prior to 8179 to use the estimated cost when receiving if the
actual cost is not set.

We set the unitprice in the table row so that it will be used when editing and will be saved even if not adjusted

To test:
1 - Add some orders to a basket, do not set actual cost field
2 - Close basket, receive orders
3 - Note actual cost field is blank
4 - Cancel receipt
5 - Apply patch
6 - Receive again
7 - Note actual cost is populated
8 - Complete receipt and confirm actual cost correctly saved

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>