Add active_enrollments field to GET /borrower/me response

Changes

• Updated endpoints:
  • GET /borrower/me: Added the active_enrollments property to the response. This new field is an array of APIEnrollment objects, providing detailed information about the borrower's current enrollments.

Definitions added:

• APIEnrollment: Object describing enrollment details with properties such as enrollment_campaign, enrollment_name, entity_id, entity_type, id, status, optional recommendations, and optional user_inputs_uuid.