[UPD] intrastat_delivery: Added a different priority order to set the Incoterm: first from the partner, then from the delivery method, and finally from the general settings; if none are set, it will remain empty.

[UPD] intrastat_delivery: Added a different priority order to set the Incoterm: first from the partner, then from the delivery method, and finally from the general settings; if none are set, it will remain empty. #848