muhhshoaib/wl 124 add front end tests for autoenrollment

I just realized that all these methods (and variables) should be in the MembershipPage section down below (line 107), not in the general InstructorDashboardPage object.

Also please make sure to make the names specific to the auto-enroll feature. I am working on a CSV file upload for cohort assignments, which will also be in the membership panel of the instructor dashboard. Therefore we will have methods in their for clicking "Browse" in the 2 different contexts, uploading files in the 2 different contexts, etc. You shouldn't assume your feature is the only "Browse" button in the membership tab.