PR description

A new metric is exported with the count of peers by client type

# HELP besu_peers_peer_count_by_type The number of clients connected by client type
# TYPE besu_peers_peer_count_by_type gauge
besu_peers_peer_count_by_type{client="Besu"} 0.0
besu_peers_peer_count_by_type{client="Erigon"} 0.0
besu_peers_peer_count_by_type{client="Geth"} 5.0
besu_peers_peer_count_by_type{client="Nethermind"} 2.0
besu_peers_peer_count_by_type{client="Nimbus"} 0.0
besu_peers_peer_count_by_type{client="Reth"} 18.0
besu_peers_peer_count_by_type{client="Unknown"} 0.0

with it you can create graphs like this one

Fixed Issue(s)

fixes #8439

Thanks for sending a pull request! Have you done the following?

• Checked out our contribution guidelines?
• Considered documentation and added the doc-change-required label to this PR if updates are required.
• Considered the changelog and included an update if required.
• For database changes (e.g. KeyValueSegmentIdentifier) considered compatibility and performed forwards and backwards compatibility tests

Locally, you can run these tests to catch failures early:

• spotless: ./gradlew spotlessApply
• unit tests: ./gradlew build
• acceptance tests: ./gradlew acceptanceTest
• integration tests: ./gradlew integrationTest
• reference tests: ./gradlew ethereum:referenceTests:referenceTests