[FIX] stock: Unwanted purchase orders

Currently, in a 2 step incoming shipments scenario, if we create a purchase order and duplicate the transfer that goes from Input to Stock, it will get the procure_method make_to_order.
This is a problem because an unwanted purchase order will be generated. 
As a solution, on the procure_method field of the stock.move, the copy is set to False. This is already the case in v15.

OPW-2952181

closes odoo/odoo#100012

Signed-off-by: Arnold Moyaux (arm) <arm@odoo.com>