[FIX] mrp: incorrect outgoing qty

- Create a new Product
- Add a BOM to this product
- Set the BOM to be a kit
- Add components to the BOM
- Create a PO for the components for a qty of 5
- Confirm the PO but don't transfer the products
- Check the phantom kits outgoing_qty and incoming_qty they will match

A Phantom Kit Products outgoing_qty and incoming_qty are identical

Closes #43447

closes odoo/odoo#43570

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