Fix issue where an attribute named length would break the use default value checkbox

Author: stijnbernards

lib/web/mage/utils/misc.js

@@ -231,7 +231,7 @@ define([
             separator = separator || '-';
 
             _.each(data, function (value, key) {
-                if (_.isObject(value) && !value.length) {
+                if (_.isObject(value) && !Array.isArray(value)) {
                     this.filterFormData(value, suffix, separator);
                 } else if (_.isString(key) && ~key.indexOf(suffix)) {
                     data[key.split(separator)[0]] = value;