[FIX] payment: do not add fee for validation transaction

When making transaction with 'validation' type and where fees
were active, fees were added to the amount.
This behaviour is problematic because
validation operations are used for tokenization for example where
no credit should charged to the customer.
Now validation operations have no fees even if fees are active
on the acquirer.

Task - 2784765

closes odoo/odoo#96712

X-original-commit: 69b04e753ab4e90e68b9d3e678ebea277586e7ac
Signed-off-by: Antoine Vandevenne (anv) <anv@odoo.com>

addons/payment/models/payment_transaction.py

@@ -206,11 +206,14 @@ class PaymentTransaction(models.Model):
                 'partner_phone': partner.phone,
             })
 
-            # Compute fees
-            currency = self.env['res.currency'].browse(values.get('currency_id')).exists()
-            values['fees'] = acquirer._compute_fees(
-                values.get('amount', 0), currency, partner.country_id
-            )
+            # Compute fees, for validation transactions fees are zero
+            if values.get('operation') == 'validation':
+                values['fees'] = 0
+            else:
+                currency = self.env['res.currency'].browse(values.get('currency_id')).exists()
+                values['fees'] = acquirer._compute_fees(
+                    values.get('amount', 0), currency, partner.country_id,
+                )
 
             # Include acquirer-specific create values
             values.update(self._get_specific_create_values(acquirer.provider, values))