[FIX] payment: open redirection in top window

When [1] was merged, it did not adapt correctly external providers
redirections. As now the /shop pages can be viewed inside an iframe, the
external redirections must be opened in the top window.

[1]: https://github.com/odoo/odoo/commit/31cc10b91dc7762e23b4bde9b945be0c4ce3fe3b

task-2687506

closes odoo/odoo#102723

X-original-commit: 3a32b9e1efa6277b345dc9239334680651690df7
Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>

addons/payment/static/src/js/payment_form_mixin.js

@@ -395,6 +395,8 @@ odoo.define('payment.payment_form_mixin', require => {
             const $redirectForm = $(processingValues.redirect_form_html).attr(
                 'id', 'o_payment_redirect_form'
             );
+            // Ensures external redirections when in an iframe.
+            $redirectForm[0].setAttribute('target', '_top');
             $(document.getElementsByTagName('body')[0]).append($redirectForm);
 
             // Submit the form
@@ -433,7 +435,7 @@ odoo.define('payment.payment_form_mixin', require => {
         _setPaymentFlow: function (flow = 'redirect') {
             if (flow !== 'redirect' && flow !== 'direct' && flow !== 'token') {
                 console.warn(
-                    `payment_form_mixin: method '_setPaymentFlow' was called with invalid flow: 
+                    `payment_form_mixin: method '_setPaymentFlow' was called with invalid flow:
                     ${flow}. Falling back to 'redirect'.`
                 );
                 this.txContext.flow = 'redirect';