Add new fields which are available to Cart Price Rules

[chrismshea]

We have a couple of attributes which can be used to build cart rules specific to Subscriptions. (Subscription Status, Subscription Interval, Subscription Re-Order ordinal)

It would be nice if we could add a few which are currently being sent to Klaviyo, and have been requested to be added to Transactional Email Template variables here.

We would not need to store these on the customer, but not sure how they would be applied to New subscription orders if not. This API endpoint responds with a number of additional customer attributes. That endpoint should be updated to have the other fields as listed in this issue.

• subscription_count
• active_subscription_count
• trial_subscription_count
• active_subscribed_qty