[IMP] account_payment: Better reference for account payment memos

The Memo field in the form view of the `account.payment` model
(the `ref` field) was a little cryptic and did not supplied a lot
of information about the payment.
After this commit the Memo will (if available) provide information
about the sales order, the partner and the payment transaction.

Task - 3063368

Part-of: odoo/odoo#105550

addons/account_payment/models/payment_transaction.py

@@ -147,7 +147,7 @@ class PaymentTransaction(models.Model):
             'payment_method_line_id': payment_method_line.id,
             'payment_token_id': self.token_id.id,
             'payment_transaction_id': self.id,
-            'ref': self.reference,
+            'ref': f'{self.reference} - {self.partner_id.name} - {self.provider_reference or ""}',
             **extra_create_values,
         }
         payment = self.env['account.payment'].create(payment_values)