fix isRedeemed when no speakers assigned (#230)

Signed-off-by: romanetar <roman_ag@hotmail.com>

Author: romanetar

app/Models/Foundation/Summit/Registration/PromoCodes/Traits/SpeakersPromoCodeTrait.php

@@ -306,9 +306,11 @@ public function isEmailSent():bool
     public function isRedeemed():bool
     {
         try {
+            if(!$this->owners->count()) return false;
+
             $query = $this->createQuery("SELECT COUNT(e.id) from models\summit\AssignedPromoCodeSpeaker e 
             JOIN e.registration_promo_code pc 
-            WHERE pc.id = :promo_code_id and e.redeemed is null");
+            WHERE pc.id = :promo_code_id AND e.redeemed is null");
 
             $query->setParameter('promo_code_id', $this->getId());
             $res = $query->getSingleScalarResult();