Users should not be able to Leave groups

Steps Go to the forum of a normal user(ex user- TopConnCustomer group - https://vanilla.topcoder-dev.com/group/128)

Actual result On the top right hand corner Leave group option is available when click on ellipses

Expected result Users should not be able to Leave groups

Final Submission Guidelines

Git issue link: https://github.com/topcoder-platform/forums/issues/90