Allow member to download submitted file for Design challenges

Describe bug: While trying to download the submitted file for Design/Idea Generation challenge, it shows following message. "Attention! The following error has occurred: Cannot Download Submission Reason: You don't have permission to perform the operation you requested."

Attached video/screenshot for reference: Error_Downloading_Submitted_file.zip

Expected behavior: When member clicks on download icon, the submitted file should be downloaded. Note that the submitted file can be downloaded through the Submission Review app but on directly on Community App. <img width="1638" alt="Screen Shot 2020-10-12 at 1 43 15 PM" src="https://user-images.githubusercontent.com/47536078/95788793-0fcfcd00-0c91-11eb-985e-5dc2f87dba44.png">

Final Submission Guidelines

Git issue link: https://github.com/topcoder-platform/community-app/issues/4212