WildFly, in itself doesn't have any integration with MongoDB. So applications are free to configure/use the drivers of their choice, the way they want to.
Having said that, there's a WildFly NoSQL project which provides a extension/subsystem for NoSQL databases GitHub - wildfly/wildfly-nosql . I haven't looked into it myself, so I'm not sure what state it is in. You might want to check the documentation to understand more https://github.com/wildfly/wildfly-nosql/blob/master/doc/README.adoc#mongodb-java-driver-versions