[Web] remove unused bcc dest column from alias table

data/web/js/site/mailbox.js

@@ -1949,11 +1949,6 @@ jQuery(function($){
           defaultContent: '',
           responsivePriority: 5,
         },
-        {
-          title: lang.bcc_destinations,
-          data: 'bcc_dest',
-          defaultContent: ''
-        },
         {
           title: lang.sogo_visible,
           data: 'sogo_visible',