Challenge Listings: MM challenge link loading legacy page

MM challenge link loading legacy page <img width="1440" alt="Screenshot 2020-05-19 at 6 27 32 PM" src="https://user-images.githubusercontent.com/58783823/82329108-71e81700-99fe-11ea-932e-bb48806e59c8.png">

Final Submission Guidelines

Git issue link: https://github.com/topcoder-platform/community-app/issues/4379