Merge pull request #19509 from edx/dsheraz/mathjax_a11y_update

cms/djangoapps/pipeline_js/js/xmodule.js

cms/static/cms/js/require-config.js

cms/static/cms/js/spec/main.js

cms/static/cms/js/spec/main_squire.js

common/static/common/js/discussion/mathjax_include.js

common/static/common/js/discussion/utils.js

...common/js/discussion/views/discussion_thread_show_view.js

...atic/common/js/discussion/views/discussion_thread_view.js

.../common/js/discussion/views/response_comment_show_view.js

...static/common/js/discussion/views/thread_response_view.js

common/templates/mathjax_include.html

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

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

common/test/acceptance/tests/discussion/test_discussion.py

common/test/acceptance/tests/lms/test_lms_problems.py

lms/djangoapps/courseware/features/problems.feature

lms/static/lms/js/spec/main.js