Dashboard: remove legacy links from dashboard

Dashboard: remove legacy links from dashboard : remove the below two links from the My dashboard page

<img width="1440" alt="Screenshot 2020-06-04 at 12 06 34 PM" src="https://user-images.githubusercontent.com/58783823/83764851-12456900-a698-11ea-8d17-30f9fbe21bfc.png"> <img width="1440" alt="Screenshot 2020-06-04 at 12 07 03 PM" src="https://user-images.githubusercontent.com/58783823/83764852-140f2c80-a698-11ea-920a-060eb3e962e2.png">

Final Submission Guidelines

Git issue link: https://github.com/topcoder-platform/community-app/issues/4470