Don't attempt to remove limited user if YoNTMA is running as LocalService

[mlynch-isec]

On uninstall, YoNTMA should check if the service is running as yontmauser before attempting to remove the limited profile. If YoNTMA was installed as LocalService, on uninstall it will still try to remove the yontmauser user/profile from the system and fail, yielding a confusing error message.