Expose `ShareConsumer.clientInstanceId(Duration)` for KIP-714 telemetry

[sobychacko]

ShareConsumer.clientInstanceId(Duration) returns a broker-assigned UUID for correlating client and broker metrics in telemetry systems. This is distinct from the client ID string (which the container already sets with -N suffixes for concurrency) — clientInstanceId is a KIP-714 telemetry identifier.

Expose this through the container so users can retrieve the telemetry instance ID for a running share consumer.