[ENT-336][ENT-337][ENT-338] Enterprise registration/login form updates

Fix [EDUCATOR-338]: Errors: "'float' object is not callable"

Merge release back to master

Christina/ed 61

Only show preview bar if student can view it.

Add Enterprise sidebar to login and registration views; remove unneeded fields; make registration form more narrow

Middleware for Monitoring Memory

up course overviews version to force refresh of table

Update branding api to add support for footer language selector

Replace urls in the welcome message.

See https://openedx.atlassian.net/browse/EDUCATOR-338
We defined max_score as a Float XBlock field, while
a method max_score exists that was getting conflicts
with it.

EDUCATOR-61

ENT-388 Fix formatting issues with LMS account activation email.

This removes extra whitespace in the body of the LMS account activation email.

ENT-388

Add single retry to compute_grades tasks.

400 for non-rescorable blocks

Learners should be able to enroll in future runs of courses in which they have an expired enrollment. Previously, the course card model populated itself by selecting the first course run in which the user was enrolled. When the user tried to enroll in another run, nothing would happen because they were already enrolled in the run the page was trying to enroll them in.

Instead of blindly choosing the first run in which the user is enrolled, we now fall through to the same behavior we use for courses in which the user is not enrolled when the user has expired enrollments.

LEARNER-933

Implement GPC signal

EDUCATOR-312 Remove flaky decorator from test_timed_exam_flow.

EDUCATOR-278 Remove flaky decorator from test_can_reset_attempts.

Condense view logic left over from removal of Waffle switch.

ECOM-6602

The new page is released and stable. The switch and old code are no longer necessary.

ECOM-7482

Update version of proctoring.

EDUCATOR-396

ENT-359 Bump enterprise package version

EDUCATOR-274

fix for issue where emails to students in one track are sent to users…