In order to enable us to remove flag_undefined_default, this updates flags according to alternatives documented in: https://github.com/edx/edx-platform/blob/master/openedx/core/djangoapps/waffle_utils/docs/decisions/0001-refactor-waffle-flag-default.rst These flags were updated with a migration: - enable_checklists_quality - REJECTED_EXAM_OVERRIDES_GRADE - ENFORCE_FREEZE_GRADE_AFTER_COURSE_END - WRITABLE_GRADEBOOK ARCHBOM-1304