When CourseNextSectionUpdate was created, it incorporated Personalized
Learner Schedules logic which didn't take into account release dates of
content and was only intended for self-paced courses that always have
all content released. This caused a bug where instructor-paced courses
could receive an update about content that had not been released yet.
This PR turns the CourseUpdateResolver back on for instructor-paced
courses so they can go back to receiving weekly highlights.