TT#14450 hide username field on edit

username cannot be edited after subscriber has been created

Change-Id: I3e1cea4d23f06af9b9f40048fee79f34d5762cd2

lib/NGCP/Panel/Controller/Subscriber.pm

@@ -2371,6 +2371,7 @@ sub edit_master :Chained('master') :PathPart('edit') :Args(0) :Does(ACL) :ACLDet
             } else {
                 $is_admin = 1;
                 $form = NGCP::Panel::Form::get("NGCP::Panel::Form::Customer::PbxExtensionSubscriber", $c);
+                $form->field('username')->inactive(1);
             }
             $pbx_ext = 1;
         }