fix(core): Fix undefined "application" array key error in user layout

Signed-off-by: Christopher Ng <chrng8@gmail.com>

core/templates/layout.user.php

@@ -24,7 +24,7 @@
 		<meta charset="utf-8">
 		<title>
 			<?php
-				p(!empty($_['pageTitle']) && $_['pageTitle'] !== $_['application'] ? $_['pageTitle'] . ' - ' : '');
+				p(!empty($_['pageTitle']) && (empty($_['application']) || $_['pageTitle'] !== $_['application']) ? $_['pageTitle'] . ' - ' : '');
 p(!empty($_['application']) ? $_['application'] . ' - ' : '');
 p($theme->getTitle());
 ?>