[Administration] Correcit switchProducer

backend/controllers/SiteController.php

         $producer = $this->getProducerContainer()->getRepository()->findOneProducerById($id);
 
         if($producer) {
-            $this->getUserModule()->getServices()->getBuilder()->switchProducer($user, $producer);
+            $this->getUserModule()->getBuilder()->switchProducer($user, $producer);
         }
         else {
             $this->addFlash('error', 'Producteur introuvable.');