[FIX] delivery: default UoM for weight
[FIX] delivery: default UoM for weight

On a picking, the UoM of the weight is the default UoM for the weight
category. However, weights in Odoo are always considered to be
kilograms.

This might lead to inconsistencies between what is displayed on the
picking and what is printed on a shipper label.

opw-702564

dfang/odoo,dfang/odoo,Elico-Corp/odoo_OCB,hip-odoo/odoo,Elico-Corp/odoo_OCB,ygol/odoo,hip-odoo/odoo,hip-odoo/odoo,ygol/odoo,laslabs/odoo,bplancher/odoo,laslabs/odoo,hip-odoo/odoo,Elico-Corp/odoo_OCB,ygol/odoo,hip-odoo/odoo,hip-odoo/odoo,bplancher/odoo,bplancher/odoo,ygol/odoo,dfang/odoo,Elico-Corp/odoo_OCB,Elico-Corp/odoo_OCB,ygol/odoo,bplancher/odoo,laslabs/odoo,ygol/odoo,dfang/odoo,bplancher/odoo,bplancher/odoo,Elico-Corp/odoo_OCB,ygol/odoo,laslabs/odoo,dfang/odoo,dfang/odoo,laslabs/odoo,laslabs/odoo