SUP-3012, [Profile] Implement "private challenge" card

-- Removed workaround code for submissionViewable field after getting it from the API response.

Author: vikasrohit

app/services/challenge.service.js

@@ -231,8 +231,6 @@ import moment from 'moment'
           if (!challenge.userHasSubmitterRole) {
             challenge.userStatus = 'COMPLETED'
           }
-          // FIXME, replace with field from response
-          challenge.submissionViewable = !challenge.isPrivate
         }
       })
     }