monitor and document the validator registration endpoint

[boulder225]

🎯 Problem to be solved

Ensure the proper monitoring and documentation of the validator registration endpoint and log line.

🛠️ Proposed solution

• Check for a panel in CDVN that monitors the submit validator registration endpoint: https://ethereum.github.io/beacon-APIs/#/Validator/registerValidator.

• Ensure it checks for successful responses, excluding 4XXs, 5XXs, or timeouts.

• Update the documentation to include instructions for users to verify the functionality of the validator registration endpoint by looking for the specific log line:
  13:10:47.094 INFO bcast Successfully submitted validator registration to beacon node {"delay": "24913h10m12.094667699s", "pubkey": "84b_713", "duty": "1/builder_registration"}