Take Exec Ed course data from course runs

[marlonkeating]

Description

Updates references for Exec Ed courses originally contained in the additional_metadata field, to now be taken from course runs.

Ticket Link

ENT-8248: update custom logic for non-ocm courses in enterprise-catalog

Outstanding Questions

• [ ] Where all should these data changes be documented?

Post-review

• [ ] Squash commits into discrete sets of changes
• [ ] Ensure that once the changes have been deployed to stage, prod is manually deployed