Merge pull request #7898 from edx/ahsan/AC-99-learner-profile-location-language-fields-accessibility

Learner profile Location and Language fields Accessibility issues

Following are done in this PR
1-The controls to edit the form fields were hyperlinks, added button and required css to
  make it look like hyperlink.
2-label added when swap to combobox
3-Non breaking spaces added with dashes.

ECOM-1772 Due date issue test case fixed.

Adding call stack manager Version-I

Updated Payment Buttons

Make course tab refreshing safer.

Re-nest for the signal-sending, then un-nest.

fix price per seat

The payment buttons now match the style of the verified upgrade buttons.

XCOM-422

Handle whitespace-only content in discussion API

Add editable_fields to discussion API responses

Fix discussion_api to handle old threads

This will allow clients to determine what actions (e.g. following,
endorsing, and editing content) a user can take on a piece of content.

The comments service rejects whitespace-only content for certain
strings, so the discussion API should also reject such content.

MA-844 Video Upload: remove dependency on AssetMetaDataStore.

Update translations (autogenerated message)

ECOM-1673 removed class and icon to always show full upsell content.

Cleanup of third-party login and auto-enrollment

removed JavaScript function specific to the upsell toggle
removed bok choy test
Removed all referenced to toggleExpandMessage()

Treat aggregate sums of None as 0

Extended hint features

Make a11y test inherit from a base class

Change publish signal test to reflect new behavior.

Update bok-choy cached db with the latest migrations

SOL-939 Jasmine Tests

mattdrayer/SOL-639: Update edx-milestones Github reference

Add professional enrollments to the instructor dashboard.

Some old threads do not have the pinned field set, which the thread
serializer should handle.