TNL-5899

This adds ability to refresh the list of uploaded videos without refreshing the whole page.

Added a refresh button that when clicked:
- fetches a fresh list of uploaded files from the server
- updates `PreviousVideoUploadListView`
- removes the successfully completed uploads from `ActiveVideoUploadListView`
- retains the ongoing or failed uploads in `ActiveVideoUploadListView` so that they can be monitored/retried

The view can also be refreshed without user action, but I felt it may be less surprising to have a button instead.

MA-333 update: auto-refresh list, fix test failure

Changes:
1. Refresh of file list triggered by upload completion. Refresh button retained and label changed to "Refresh List".
2. Added `aria-live="polite"` to `.active-video-upload-list` and `.assets-table`.
3. Removed unused parameter `evt`.
4. Added self to the `AUTHORS` file.

MA-333 update: added tests

MA-333 update: removed refresh button

MA-333 update: address review comments of @mushtaqak

MA-333 update: simplify nested `_each`

MA-333 update: rename viewRefresh to isViewRefresh

MA-333 update: doc string for `clearSuccesful`

MA-333 update: fix accessibility

MA-333 update: update only successfully uploaded videos

MA-333 update: use window.SR feature to notify screen readers that video upload was successful (@pomegranited)

Previously, retry() was never called, so the task was never retried despite
defining several retry-related variables.

Note: this used to be in common, but it was only used in Studio.

TNL-5083

It should help catch unicode encoding problems earlier.

This also updates python-saml dependency to a version that includes a
patch for unicode strings.

The `commit` argument had already been removed from code [1][2][3],
prompted by the django18 upgrade.

[1] https://github.com/edx/edx-platform/pull/10927
[2] 07f015bb
[3] a4006c86

FEDX-176

Replaced lettuce tests with bokchoy tests for the course updates page and improved flaky test issues.
TNL-5051

Removes most remaining hardcoded references to XSeries from the LMS. Part of ECOM-4638.

ECOM-4890

Basic architecture of Maintenance App - SUST-19, SUST-42. Implement Force Publish Course view. SUST-46

Adds ENABLE_SUBSECTION_GRADES_SAVED feature flag to both lms and cms. Also
installs the wiring that will allow robust grades to be used for courses
that enable it. This functionality is still gated by the feature flag
and should not be used until the remaining robust grades work is finished.

Revert "Basic architecture of Maintenance App - SUST-19, SUST-42. Implement Force Publish Course view. SUST-46"

This reverts commit 27646b7e.