[FIX] stock: default location for scrap

- Create a default value for 'Source Location' or 'Scrap Location'
- Create a Scrap Order

the default value is not taken into account since it is overridden by
`_onchange_company_id`.

We avoid changing the location in case the company matches.

opw-2189578

closes odoo/odoo#44753

Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>