JI-3620 Refactor use of glorified loop

The editor widgets relies on references to the parameter objects, 
changing the parameter object without updating the references means 
that the editor widgets will continue updating objects that won't be saved.

Author: icc

scripts/h5peditor-form.js

@@ -351,9 +351,9 @@ ns.Form.prototype.setSubContentDefaultLanguage = function (params, lang) {
   const self = this;
 
   if (Array.isArray(params)) {
-    params = params.map(function (listItem) {
-      return self.setSubContentDefaultLanguage(listItem, lang);
-    });
+    for (let i; i < params.length; i++) { 
+      params[i] = self.setSubContentDefaultLanguage(params[i], lang);
+    }
   }
   else if (typeof params === 'object') {
     if (params.metadata) {