[FIX] stock: qty in pack operations
[FIX] stock: qty in pack operations

- Enable lot tracking on Product A
- UoM of Product A is kg, but Purchase UoM is lb(s)
- Create a PO for 200 lb(s) of Product A, confirm
- Go in the picking: 200.01 lb(s) shuold be received according to the
  pack operation, while 200.00 lb(s) are expected in the stock move.

The field `product_qty` on the sotck move contains the quantity in kg,
but already rounded from the value in lb(s). If we convert it back to
lb(s), there might obviously be a rounding error, since we do:
lb(s) -> kg -> lb(s)

To solve this, we recompute the quantity in the UoM of the product
without rounding, as a temporary computational value.

opw-705259

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