[FIX] mrp: default location

- Create a picking type with specific default locations, for type
  Manufacturing
- Go to Inventory, click on the 'To Process' button
- Create a MO

The default locations are not taken into account.

This is because the default picking type is not in the context.

opw-2128182

closes odoo/odoo#41035

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