[lib] [9/n] Move ConnectionInitializationResponse and Heartbeat types out of lib tunnelbroker into shared websocket folder

Summary:
Similar to what was done for ConnectionInitializationResponse/Status and Heartbeat rust implementations in Shared, we've moved their javascript types into a shared websocket folder for usage by identity search types

Depends on D10875

Test Plan: flow

Reviewers: varun, bartek, kamil

Reviewed By: bartek, kamil

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D10878