ONCEHUB-98709 Prevents processing of 'Email sent to guest' tracking events when the destination is mixpanel.

Author: ArjavJain27

src/util/oncehub-custom-transformer.js

@@ -64,6 +64,11 @@ const oncehubTransformer = (destination, event) => {
     return null;
   }
 
+  if (event.message.type === EventType.TRACK && event.message.event === 'Email sent to guest' && destination === "mp") {
+    // eslint-disable-next-line no-param-reassign
+    return null;
+  }
+
   changeDateFormatForCustomerio(
     contextTraitsPresent,
     eventTraitsPresent,