[FIX] l10n_it_stock_ddt : fixed ddt report quantity

Currently, DDT use the product_uom_quantity of product for the ddt move which is inaccurate in case of no-backorder change in quantity

The fix correctly check if the done quantity is other than 0 for the delivery and if it is, use it as the delivery quantity

opw-2663174

closes odoo/odoo#78184

Signed-off-by: Florian D <fdamhaut@users.noreply.github.com>