Migrate courseware payload to v3

[dennis531]

Version
master

Describe the bug
The payload of the courseware blocks are unchanged after updating from version 2 to 3. It is related to the problem in #1147 and is caused in migration 77.

Actual payload:

{"series_id":"123456","episode_id":"98765"}

Expected payload:

{"token":"12334567","visible":"internal"}