[FIX] product: fix speed of _set_product_template_value_ids compute
[FIX] product: fix speed of _set_product_template_value_ids compute

The method was doing an unnecessary sort since the _order has been fixed in
f8dad1bb4b712d8f34035420ef1f6e484c638f5b

Moreover, it tried to find the ptav through the attribute_id related field and
a map on the other side, instead of directly relying on the ids of the ptv.

opw-1923999
task-1922055
PR: #30274
ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo