[FIX] purchase: recompute qty_received_method

qty_received_method is not recomputed if the product type change, and can lead to issues on existing purchases when trying to generate a Vendor Bill.

# HOW TO REPRODUCE:
- Create product P, type: Service, Control Policy: 'On Received Qty'
- Create PO for 1 unit of P (do not confirm)
- Update type of P to Storable
- Confirm PO, Receive Products
=> Qty Received is 0, not able to generate Bill

closes odoo/odoo#119622

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