CLI do no list un-created user admin

https://github.com/FreshRSS/FreshRSS/issues/1448

cli/list-users.php

@@ -4,7 +4,7 @@ require('_cli.php');
 
 $users = listUsers();
 sort($users);
-if (FreshRSS_Context::$system_conf->default_user !== '') {
+if (FreshRSS_Context::$system_conf->default_user !== '' && in_array(FreshRSS_Context::$system_conf->default_user, $users, true)) {
 	array_unshift($users, FreshRSS_Context::$system_conf->default_user);
 	$users = array_unique($users);
 }