Hi! How can I add a subscribers date/time they joined CK into a custom field using Liquid in an automation? I see in the CK API there is a "created_at" but don't know how to reference it in Liquid. I tried {{ subscriber.created_at }} but didn't work. I've done the following {{ "now" | date: "%m-%d-%Y" }} in an automation to put the date into a custom field and it works, but would rather get the value the API shows for ‘created_at’ Thanks!