[14.0] account_payment_purchase: changing many2one resets payment_mode

[ae-landoo]

Hi,
We've seen that when the field purchase_vendor_bill_id is changed and a purchase is selected from it, the payment_mode_id is always reseted because it is using the reference purchase_id.
new_mode = self.purchase_id.payment_mode_id.id or False
We've made this change, and it seems to work as it should.
new_mode = self.purchase_vendor_bill_id.purchase_order_id.payment_mode_id.id or False
The same goes for the partner_bank_id field.
@MiquelRForgeFlow

[Mat-moran]

We have test your solution and it works OK. We are going to propose PR, if you prefer to do it yourself just remove ours.
Thanks @ae-landoo

[ae-landoo]

Just do it by yourself, it is ok for us.
Best regards @Mat-moran