Subcommunity filter does not include private groups

Subcommunity filter does not include private groups https://www.topcoder.com/challenges? https://beta-community-app.topcoder.com/challenges?

cc @lakshmiathreya @Oanh-and-only-Oanh @sushilshinde

<img width="1440" alt="Screenshot 2020-07-16 at 10 19 56 AM" src="https://user-images.githubusercontent.com/58783823/87628277-304dc100-c74e-11ea-9e52-a80b7e05fdfd.png"> <img width="1440" alt="Screenshot 2020-07-16 at 10 20 39 AM" src="https://user-images.githubusercontent.com/58783823/87630511-e3201e00-c752-11ea-9b25-51bbb1476580.png">

Final Submission Guidelines

Git issue link: https://github.com/topcoder-platform/community-app/issues/4650