Fix logic that determines whether to apply HTTP caching headers based on Symphony user logged in status

Author: DavidOliver

extension.driver.php

@@ -321,7 +321,7 @@ public function addCSS($context) {
 	public function updateHeaders() {
 
 		// Don’t override/set HTTP caching headers if Symphony user is logged in
-		if (!Frontend::instance()->isLoggedIn()) {
+		if (Frontend::instance()->isLoggedIn()) {
 			return false;
 		}