Check and Improve Beacon Node Health Status Logic

[boulder225]

🎯 Problem to be solved

The current implementation of the Beacon Node Health Status logic in Charon does not consider the number of connected peers. As a result, a Beacon Node with zero peers is still reported as having a "Health Status" of OK, which may not reflect the operational status of the node.

Resources

This cluster has a Health Status OK despite zero peers in BN (which is supposed to be a health status).

Per the docs for the /readyz endpoint (which is used for the Health Status gauge)

"Set to 1 if the node is operational and monitoring api /readyz endpoint is returning 200s. "
"Else /readyz is returning 500s and this metric is either set to "
"2 if the beacon node is down, or"
"3 if the beacon node is syncing, or"
"4 if quorum peers are not connected."

🛠️ Proposed solution

• Implement a check for the minimum required number (at least 3) of connected peers
• Update the Health Status logic to consider a Beacon Node with zero peers as unhealthy
• Determine the appropriate Health Status value or error code for a Beacon Node with zero peers