[APER-3228]
This PR tries to correct bad data on a course update before it enters the system. There are times when we are updating a course (via Studio) and we save bad data that has been persisted and passed to the backend from the CMS's legacy Django template-based frontend.
The bad data doesn't affect the LMS or CMS much, as there is extra logic in the monolith around course pacing. However, downstream services (e.g. Credentials) don't understand the concept of course pacing and will persist bad data (like a certificate available date associated with a self-paced course run).
The most common problem that manifests is that Credentials will hide a certificate from a learner on their Learner Record, even though the course certificate is visible and accessible to the learner from the LMS.
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