CNG-6: Add refId parameter to inform MindTap which actvity is updated. This did not solve the problem yet, so further changes will be needed.
Additional changes: Add "noopener" parameter to notifyCloseURL in Learner so it knows whether to change location of own window or opener window. Make exception more informative about no MindTap external server configured, so no calls to LoginRequestServlet can be made. Fix the call to Pedagogical Planner when editing an activity.