Ongoing challenge bucket also includes open for registration challenges

Ongoing challenge bucket also includes open for registration challenges <img width="1440" alt="Screenshot 2020-09-21 at 8 10 12 PM" src="https://user-images.githubusercontent.com/58783823/93781102-a0912b00-fc46-11ea-9ae7-14953d26300e.png">

Final Submission Guidelines

Git issue link: https://github.com/topcoder-platform/community-app/issues/4975