web: remove Link of username in site admin area on dotcom

Created by: unknwon

This PR removes the Link of username in Site admin > Users page on Sourcegraph.com due to the fact site admins will see a 403 page anyway and the "Settings" button has been removed in https://github.com/sourcegraph/sourcegraph/pull/27399.

Please feel free to suggest or direct push if there is a better syntax for achieving this!