[FIX] stock_landed_costs: missing required account on invoice line

before this commit, on creating a vendor bill with
landed cost product, is not allowing to save the bill,
it shows the exception that missing required account
on accountable invoice line.

steps to reproduce:

* create a product category with inventory
valuation set as Manual
* create a landed cost product using above category
* enable anglo saxon accounting in accounting settings
* create a vendor bill with this product and click save
* exception is shown: missing required account
on accountable invoice line

after this commit, the exception wont be shown

closes odoo/odoo#117474

Signed-off-by: William Henrotin (whe) <whe@odoo.com>