The marketing site currently cannot use the entitlement
api to determine whether a user has an unfilled entitlement.
Including the entitlement enrollment_course_run makes this
information accessible to consumers of the entitlement API.
Learner-3731
The Entitlement API will allow for GET, POST, DELETE(Revoke), and
variations of these methods of managing and retrieving data about
Learner Entitlements.
[LEARNER-2661]