[services] Tunnelbroker - Remove cryptopp from dependencies

Summary:
This diff removes the deprecated C++ cryptopp library from the dependencies.
In D5947 we are switched to using the Rust function for the signed string verification and we don't need the cryptopp and related C++ code base anymore.

Linear task: ENG-2492

Test Plan: Passing CI gates.

Reviewers: O1 Nix, jon, bartek, varun, ashoat

Reviewed By: O1 Nix, varun, ashoat

Subscribers: ashoat, tomek, atul

Differential Revision: https://phab.comm.dev/D5949