Fix missing class on cancelSubscription exception

CRM/Core/Payment/Stripe.php

@@ -1084,7 +1084,7 @@ class CRM_Core_Payment_Stripe extends CRM_Core_Payment {
   public function cancelSubscription(&$message = '', $params = []) {
     $propertyBag = \Civi\Payment\PropertyBag::cast($params);
     if (!$propertyBag->has('recurProcessorID')) {
-      throw new PaymentProcessorException("cancelSubscription requires the recurProcessorID");
+      throw new \Civi\Payment\Exception\PaymentProcessorException("cancelSubscription requires the recurProcessorID");
     }
 
     // contributionRecurID is set when doCancelRecurring is called directly (from 5.25)