Remove trailing space (#886)

Model/Notification.php

@@ -43,7 +43,7 @@ class Notification extends \Magento\Framework\Model\AbstractModel implements Not
     const POSAPPROVED = 'POS_APPROVED';
     const HANDLED_EXTERNALLY = 'HANDLED_EXTERNALLY';
     const MANUAL_REVIEW_ACCEPT = 'MANUAL_REVIEW_ACCEPT';
-    const MANUAL_REVIEW_REJECT = 'MANUAL_REVIEW_REJECT ';
+    const MANUAL_REVIEW_REJECT = 'MANUAL_REVIEW_REJECT';
     const RECURRING_CONTRACT = "RECURRING_CONTRACT";
     const REPORT_AVAILABLE = "REPORT_AVAILABLE";
     const ORDER_CLOSED = "ORDER_CLOSED";