Re-work "Complete Challenge for Players" UI

Currently, if I click on the "Complete Challenge for Players" button it opens a new page for me to submit the necessary details. It would be nice if this whole page was just a pop-up/modal window (like the Image Library) on the Topic Manager page directly so that I don't lose my spot on the Challenge List. The "Single Player" and "Multiple Player" pages can also be separated into 2 tabs within the pop-up/modal to reduce the clutter.

Added a screenshot of the "Complete Challenge for Players" page for easy reference.