Fix syntax error in de_xmpp_user_list.lng

interface/web/mail/lib/lang/de_xmpp_user_list.lng

 <?php
 $wb['list_head_txt'] = 'XMPP-Benutzerkonten';
 $wb['jid_txt'] = 'Jabber-ID';
-$wb['is_domain_admin_txt'] = 'Domänen-Administrator;
+$wb['is_domain_admin_txt'] = 'Domain-Administrator';
 $wb['is_muc_admin_txt'] = 'MUC-Admin';
 $wb['add_new_record_txt'] = 'Neuen Benutzer hinzufügen';
 $wb['active_txt'] = 'Aktiv';