Merge pull request #5281 from edx/adam/hide-tabs-if-not-enrolled-rebase-2

common/djangoapps/embargo/tests/test_middleware.py

common/lib/xmodule/xmodule/tabs.py

common/lib/xmodule/xmodule/tests/test_tabs.py

lms/djangoapps/courseware/courses.py

lms/djangoapps/courseware/middleware.py

lms/djangoapps/courseware/tests/test_about.py

lms/djangoapps/courseware/tests/test_course_info.py

lms/djangoapps/courseware/tests/test_middleware.py

lms/djangoapps/courseware/tests/test_tabs.py

lms/djangoapps/courseware/views.py

lms/djangoapps/django_comment_client/forum/tests.py

lms/djangoapps/django_comment_client/forum/views.py

lms/envs/common.py

lms/templates/courseware/course_navigation.html

lms/templates/courseware/info.html

lms/templates/help_modal.html