Add the current chain id as a label to the metrics

Issue type

Feature Request

Have you reproduced the bug with the latest dev version?

Yes

Version

main

Custom code

Yes

OS platform and distribution

No response

Describe the issue

When a host participates on multiple subnets, or changes to a different subnet, it would be really useful to know the chain the metrics are associated with.

Cometbft already does this, so reusing their label and value creation would be preferred.

Repro steps

Observe the output generated from the metrics endpoint.

Relevant log output