refactor: Don't access $_SESSION directly for Auth (#8513)

* Don't access $_SESSION directly for Auth

* fix style

* add property annotations

html/ajax_ossuggest.php

@@ -15,8 +15,10 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+use LibreNMS\Authentication\Auth;
+
 session_start();
-if (!isset($_SESSION['authenticated'])) {
+if (!Auth::check()) {
     die('Unauthorized.');
 }