Merge pull request #15143 from edx/andya/breadcrumb-improvements

common/lib/xmodule/xmodule/js/src/sequence/display.js

...n/static/common/templates/sequence-breadcrumbs.underscore

...n/static/sass/edx-pattern-library-shims/_breadcrumbs.scss

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

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

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

lms/djangoapps/courseware/tests/test_views.py

lms/djangoapps/courseware/views/index.py

lms/static/sass/_build-lms-v1.scss

lms/static/sass/course/courseware/_courseware.scss

lms/static/sass/shared/_header.scss

lms/templates/courseware/courseware.html

lms/templates/search/search_error.underscore

...ookmarks/templates/course_bookmarks/course-bookmarks.html

openedx/features/course_experience/__init__.py

.../templates/course_experience/course-updates-fragment.html

themes/edx.org/lms/templates/header.html