Predicate isInsecureMailPropertyConfig

The insecure way to set Java properties in mail sessions.

1. Set the mail.smtp.auth property to provide the SMTP Transport with a username and password when connecting to the SMTP server or set the mail.smtp.ssl.socketFactory/mail.smtp.ssl.socketFactory.class property to create an SMTP SSL socket.
2. No mail.smtp.ssl.checkserveridentity property is enabled.