[FIX] product: Correct ID retrieval in contact price list calculation when changing province

How to reproduce the error:
    1. Go to Contacts.
    2. Select a Contact of Type Company:
       Find and select a contact that is a company type and to which a
       price list has already been set up previously.
       In case no price list has been set previously, set the price list
       and save the contact.
    3. Edit the contact and modify the address state without the need to
       save the changes.
    4. View the PriceList:
       After changing the province, look at the price list field. You can
       verify that the price list has become blank immediately after making
       the change in state, without the need to save the changes.

Current behaviour: the price list is deleted when the state of the address is changed.

Expected behaviour: keep the previously set price list.

Explanation:

The code was incorrectly using "p.id" instead of "p._origin.id" to get
the contact ID. This resulted in a non-existent key being retrieved and
caused the loss of the price list in the contact when changing the province.
The fix adjusts the code to correctly use "p._origin.id", ensuring correct
retrieval of the ID and avoiding unwanted changes to the price list.

Example of data obtained by debugging:

- Edited user: Deco Addict
- Data obtained in "res": res {53: product.pricelist(1,)}
- Data retrieved in "p.id": (p.id) > NewId_53
- Data retrieved at "p._origin.id": (p._origin.id) > 53

TT47536

closes odoo/odoo#153326

X-original-commit: 570715ecc6c9b105a2edaed23a68f557e5cf1987
Signed-off-by: Victor Feyens (vfe) <vfe@odoo.com>

addons/product/models/res_partner.py

@@ -22,7 +22,7 @@ class ResPartner(models.Model):
     def _compute_product_pricelist(self):
         res = self.env['product.pricelist']._get_partner_pricelist_multi(self.ids)
         for partner in self:
-            partner.property_product_pricelist = res.get(partner.id)
+            partner.property_product_pricelist = res.get(partner._origin.id)
 
     def _inverse_product_pricelist(self):
         for partner in self: