Changes to * POST /api/v0/exercise-services/client/exercises/:id/submit * * Accepts an exercise submission from the user. A `file` answer names files previously stored * through this exercise's `files` endpoint, in the order they are to be graded; those files are the * answer. An answer that names no files is a JSON answer, carried in `data_json`.

the response property message became required for the status 401

the response property message became required for the status 403

the response property message became required for the status 404

the response property message became required for the status 422

the response property message became required for the status 426

the response property message_key became required for the status 401

the response property message_key became required for the status 403

the response property message_key became required for the status 404

the response property message_key became required for the status 422

the response property message_key became required for the status 426

the response property type became required for the status 401

the response property type became required for the status 403

the response property type became required for the status 404

the response property type became required for the status 422

the response property type became required for the status 426

removed the request property uploaded_file_ids

added the new optional request property answer_kind

added the new optional request property data_files

added the new optional request property data_json