Visitor : optimisation filtre par cookie

Repository/User/VisitorRepositoryQuery.php

 
     public function filterByCookie(string $cookie = null)
     {
-        return $this
+        if(is_null($cookie)) {
+            return $this->andWhere('.cookie IS NULL');
+        }
+        else {
+            return $this
                 ->andWhere('.cookie LIKE :cookie')
                 ->setParameter('cookie', $cookie);
+        }
     }
 
     public function filterByLastAccess(\DateTime $lastAccess)