WW-4447 Reverts some changes introduced by WW-4297

Resetting 'label' attribute can block user if they would like to
develop their own hidden.ftl template

core/src/main/java/org/apache/struts2/components/Hidden.java

@@ -66,10 +66,4 @@ public class Hidden extends UIBean {
         return TEMPLATE;
     }
 
-    @Override
-    public void evaluateParams() {
-        super.evaluateParams();
-        label = null;
-        addParameter("label", null);
-    }
 }