Fix the filter method in the commerce coupon redemption form template

Problem/Motivation

The file commerce-coupon-redemption-form.html.twig is not implementing the twig filter method correctly.

The filter arguments must be (coupon, key) in order to work correctly.

It is already done in Drupal Commerce.

Proposed resolution

Replace form.coupons|filter(key => key|first != '#' ) by form.coupons|filter((coupon, key) => key|first != '#' )