safety checks for session_start

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

Author: eug-L

prestashop8.x/tawkto.php

@@ -101,7 +101,9 @@ private function installTab()
      */
     public function hookDisplayFooter()
     {
-        session_start();
+        if (session_status() === PHP_SESSION_NONE && !headers_sent()) {
+            session_start();
+        }
 
         $current_widget = self::getPropertyAndWidget();
         if (empty($current_widget)) {