Merge pull request #14343 from edx/efischer/hide_after_end

cms/djangoapps/contentstore/views/item.py

cms/static/js/views/modals/course_outline_modals.js

cms/templates/js/content-visibility-editor.underscore

cms/templates/js/course-outline.underscore

common/lib/xmodule/xmodule/seq_module.py

common/lib/xmodule/xmodule/tests/test_sequence.py

common/test/acceptance/pages/lms/courseware.py

lms/djangoapps/course_blocks/transformers/hidden_content.py

lms/djangoapps/courseware/tests/test_views.py

lms/templates/hidden_content.html