fix early flush causing database insert while object if not ready yet

src/Admin/AdherentAdmin.php

@@ -533,7 +533,8 @@ class AdherentAdmin extends AbstractAdmin
                     
                     $adherent->setAnonymousToken($uniqueCode);
                     $em->persist($adherent);
-                    $em->flush();
+                    //Flushing here in case of new adherent creation will cause an immediate insert of a user with password in db, which is not permitted.
+                    //Flushing here is not required as it is done later.
                 }
             }
         });