[services] Tunnelbroker - Removing of get and send methods from API and native codebase

Summary:
This diff removes deprecated API methods from the Tunnelbroker API including the proto file and calls from the native codebase.
Deprecated API methods that should be removed:

• Send
• Get (stream)

These methods were added prior 0.5 version and were deprecated in a favor of the single bidirectional stream.

These diff changes take place in:

• The protobuff file and its generated ones - by removing the API calls;
• Native C++ network client-related codebase - by removing the API-related methods;
• Tunnelbroker Rust gRPC server - by removing the empty handlers for the old API.

Linear task: ENG-1334

Test Plan: Services and native iOS and Android builds are successful.

Reviewers: atul, tomek, jon

Reviewed By: atul, tomek

Subscribers: ashoat, tomek, atul

Differential Revision: https://phab.comm.dev/D5684