restore blackfire condition to avoid critical logs

public/index.php

@@ -42,10 +42,10 @@ $response->send();
 $kernel->terminate($request, $response);
 
 // If the header is set
-//if (isset($_SERVER['HTTP_BLACKFIRETRIGGER'])) {
+if (isset($_SERVER['HTTP_BLACKFIRETRIGGER'])) {
     // When runtime shuts down, let's finish the profiling session
     register_shutdown_function(function () use ($blackfire, $probe) {
         // See the PHP SDK documentation for using the $profile object
         $profile = $blackfire->endProbe($probe);
     });
-//}
+}