[commtest] Get rid of hardcoded ClientPublicKeys values
Summary:
Depends on D12342
Removed hardcoded ClientPublicKeys constants and replaced usages with new implementation
Test Plan: Commtest
Reviewers: kamil, will, varun, marcin
Reviewed By: kamil
Subscribers: ashoat, tomek
Differential Revision: https://phab.comm.dev/D12343