Investigate the failing of fluffy local testnet test when ran with slightly larger ENRs

[kdeme]

This PR adds a small client & version string in the ENR for debug purposes on the public testnet. However, it never got merged because this slight increase of ENR size causes the local testnet tests to fail.

This is likely due to a cascading effect somewhere in the amount of requests that probably increased as slightly less ENRs (1 less) will now fit in a FindNodes requests (I assume).