When SSL mode is preferSSL, log connections that do not use SSL

When a client makes a SSL connection to the host, with certificate or not, the client metadata captured in the log does not contain SSL related information, except SERVER-24176 which logs the peersubjectName only when the client has provided a valid certificate. For a MongoDB configurations that allow SSL and non-SSL connections, this is very difficult for admins to identify if a connection from a client is SSL encrypted or not.
It would be very useful to flag the SSL connection details for all types of SSL connections.