I added customer field in pos.payment.method and i need to use it in the payment when pay in session to prevent requesting customer when i a click on validate button after choosing payment method which has identify customer field equal true i added this code in js to take customer from the selected payment method but it doesn't work odoo15 

odoo.define('custom_st_customer.SetDefaultCustomer', function(require) {
    "use strict";

    var models = require('point_of_sale.models');

    models.load_fields('pos.payment.method', 'default_partner_id');

    var _super_order = models.Order.prototype;
    models.Order = models.Order.extend({
        initialize: function(attributes, options) {
            _super_order.initialize.apply(this, arguments);

            // Set the default customer when selecting a payment method
            this.paymentlines.on('change:selected_paymentline', this, this._onSelectedPaymentlineChange);
        },

        _onSelectedPaymentlineChange: function() {
            var paymentMethod = this.selected_paymentline.payment_method;
            if (paymentMethod && paymentMethod.default_partner_id && !this.get_client()) {
                var defaultPartner = this.pos.db.get_partner_by_id(paymentMethod.default_partner_id[0]);
                if (defaultPartner) {
                    this.set_client(defaultPartner);
                }
            }
        },
    });
});