[IMP] stock_account: cost field editable on FIFO + AUTO
[IMP] stock_account: cost field editable on FIFO + AUTO

Before this commit, when 'Inventory Valuation' was on 'Automated' and
'Costing Method' was on FIFO, the product cost field wasn't editable
anymore.
Now, it still editable in this configuration (other configuration aren't
affected).

Task #1937164

closes odoo/odoo#31145

Signed-off-by: Simon Lejeune (sle) <1969d8dff896674c2d819e813f5e88ca826229ab@openerp.com>
ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo