feat(medusa-plugin-sendgrid) Add refund created event to sendgrid (#2740)

packages/medusa-plugin-sendgrid/src/subscribers/order.js

@@ -13,6 +13,7 @@ class OrderSubscriber {
     this.notificationService_.subscribe("swap.created", "sendgrid")
     this.notificationService_.subscribe("order.items_returned", "sendgrid")
     this.notificationService_.subscribe("order.return_requested", "sendgrid")
+    this.notificationService_.subscribe("order.refund_created", "sendgrid")
   }
 }