[FIX] purchase: add source document to vendor bill

Create a purchase order, confirm it and create the vendor bill. The
source document will be not filled.

Fixing the related variable and changing also the missing reference to
the partner

opw-2197272

closes odoo/odoo#45534

X-original-commit: 8498dbe10db87f718b9287f69188c627e36f98a3
Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>

addons/purchase/models/purchase.py

@@ -426,8 +426,8 @@ class PurchaseOrder(models.Model):
             # Do not set an invoice_id if we want to create a new bill.
             if not create_bill:
                 result['res_id'] = self.invoice_ids.id or False
-        result['context']['default_origin'] = self.name
-        result['context']['default_reference'] = self.partner_ref
+        result['context']['default_invoice_origin'] = self.name
+        result['context']['default_ref'] = self.partner_ref
         return result