[FIX] l10n_it_stock_ddt: account for pricelist in the DDT report

Bug:
When printing DDT documents for a delivery with a pricelist applied, the
total value shown comes from the product's original price and not the
modified pricelist price.

Setup:
- install `sale_management` and `l10n_it_stock_ddt`
- have a product P with a price A
- create a pricelist that where P has a price B

Steps to reproduce:
- activate DDT report printing
- create a quotation set the pricelist you created and the product P
- validate the quotation
- go to the associated delivery and validate it
- print the DDT report

You should see that the price mentioned on the DDT report does not
account for the pricelist. (price A is shown, instead of B)

opw-3171295

closes odoo/odoo#121424

Signed-off-by: Josse Colpaert <jco@odoo.com>