update bok choy db caches
Replace `check_for_get_code` with `assert_request_status_code`

More flexible, uses the word "assert", method instead of function
Refactor LMS Video Tests
Decrease Video Player Init Wait Timeout
make expanding explanation accessible

LMS-11161
Toggle aria-expanded attribute
Annotation Tools: Added Grouping Plug-In

- adding comments

 - spacing issues and indentation
Merge pull request #4504 from lduarte1991/lduarte-harvardx-pr11

Annotation Tools: Added Grouping Plug-In
update bok choy db caches
Merge branch 'mvo/update_bok_choy_db_caches' of https://github.com/edx/edx-platform into mvo/update_bok_choy_db_caches
Merge pull request #4636 from edx/mvo/update_bok_choy_db_caches

update bok choy db caches
Merge pull request #4715 from edx/ammar/decrease-video-player-init-timeout

Decrease Video Player Init Wait Timeout
Merge pull request #4261 from edx/ammar/video-tests-refactoring

Refactor Bok-Choy LMS Video Tests
Fix property call issue
Merge pull request #4731 from edx/ammar/fix-property-call

Fix property call issue
Catch InvalidKeyError in UserTagsEventContextMiddleware.

LMS-11189
Catch InvalidKeyError in static_tab view.

LMS-11189
Merge pull request #4678 from edx/usman/lms11189-user-api-middleware-exception-2

Catch InvalidKeyError in UserTagsEventContextMiddleware and static_tab view.
Merge pull request #4654 from edx/db/kill-check-for-code

Replace `check_for_get_code` with `assert_request_status_code`
Merge pull request #4602 from edx/db/expand-on-click-or-enter

make expanding explanation accessible