feat: Add redirect to enterprise learner dashboard (#1251)

When a learner tries to load the B2C course page for a course that
starts in the future (error_code="course_not_started"), normally the
learning MFE automatically redirects to the B2C dashboard.  This change
supports an alternate error_code "course_not_started_enterprise_learner"
to trigger an alternative redirect to the B2B (enterprise) learner
dashboard.

This does two main things:

1. When the course metadata API response indicates
   course_access.error_code = "course_not_started_enterprise_learner"
   then redirect to "/redirect/enterprise-learner-dashboard".
2. When the top-level router matches path "/redirect/enterprise-learner-dashboard"
   then redirec to to the value of config `ENTERPRISE_LEARNER_PORTAL_URL`.

ENT-8078

global-setup.js

@@ -0,0 +1,4 @@
+// Force all tests to run in UTC to prevent tests from being sensitive to host timezone.
+module.exports = async () => {
+  process.env.TZ = 'UTC';
+};