Add CommunicationFault to AuthTokenValidator

[corneliusclaussen]

Describe your changes

This adds an error to the auto token validator interface to be used by hardware implementations to report the communication is lost.

Issue ticket number and link

Checklist before requesting a review

• [X] I have performed a self-review of my code
• [ ] I have made corresponding changes to the documentation
• [X] I read the contribution documentation and made sure that my changes meet its requirements