Remove connected clients from the user upon logout through the UI button

[jcocchi]

When logging out through the UI button the call to INotificationService.LogOut() is never made causing the connected clients to never be cleaned up in the database and the user's status not being updated to "offline"

Currently the button will submit a form that does a post request to the Account/Logoff function, determine the best way to add the call, either in the account controller or on the js side