[FIX] account: account_invoice_report: make the calculation of product_qty right
[FIX] account: account_invoice_report: make the calculation of product_qty right

Before this commit product quantity was computed as if the uom on the product represented the *unit* in which a product was sold
Hence, in the report, it produced something like this:
I sell 10 packages of something, which is sold essentially by 10 itself = which makes a total unitary quantity of 100
This wrong behavior has been introduced in 10.0 by 9c5d4cd60cc414a52c52b0f3d0048be535769838

After this commit, the computation is done to match the *standard* unit of measure in which a product quantity is *represented*

OPW 741745

Closes #16834

hip-odoo/odoo,ygol/odoo,hip-odoo/odoo,ygol/odoo,ygol/odoo,hip-odoo/odoo,hip-odoo/odoo,ygol/odoo,ygol/odoo,ygol/odoo,hip-odoo/odoo,hip-odoo/odoo,ygol/odoo