[lib] remove unused Tunnelbroker message validators

Summary:
ENG-8621.

All files here are messages sent from Device to Tunnelbroker, validation takes place on Rust side and tcomb code is not needed.

Depends on D12856

Test Plan: N/A

Reviewers: bartek, tomek

Reviewed By: tomek

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D12857