When NB_FORCE_RELAY is enabled, skip WorkerICE creation entirely,
suppress ICE credentials in offer/answer messages, disable the
periodic ICE candidate monitor, and fix isConnectedOnAllWay to
only check relay status so the guard stops sending unnecessary offers.
When an ICE agent connection was in progress, new offers were being ignored. This was incorrect logic because the remote agent could be restarted at any time.
In this change, whenever a new session ID is received, the ongoing handshake is closed and a new one is started.
