[Services] Update tunnelbroker reference to protos

Summary:
Update tunnelbroker build to
reference new protobuf location.

https://linear.app/comm/issue/ENG-1231

Depends on D5041 D4992

Test Plan:

nix develop
cd services/tunnelbroker
rm -rf build && mkdir build && cd build && cmake .. && make -j

Existing tunnelbroker CI gate

Reviewers: atul, max, abosh, varun, karol

Reviewed By: atul

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D5042