Similar fix for customer_reference field

InvenTree/order/templates/order/sales_order_base.html

@@ -163,6 +163,7 @@ $("#edit-order").click(function() {
             customer: {
             },
             {% endif %}
+            customer_reference: {},
             description: {},
             target_date: {
                 icon: 'fa-calendar-alt',

InvenTree/templates/js/order.js

@@ -14,6 +14,7 @@ function createSalesOrder(options={}) {
             customer: {
                 value: options.customer,
             },
+            customer_reference: {},
             description: {},
             target_date: {
                 icon: 'fa-calendar-alt',