Fix failing execution tests with latest geth version

[jimmygchen]

We made a workaround to use geth v1.10.10 instead of master to get CI to pass for the time being:

#6936

Our tests need to be updated to work with latest geth, due to these breaking changes:

• removal of personal namespace in v1.14.12: See #30704
• removal of totalDifficulty field from RPC in v1.14.11. See #30386.

[michaelsproul]

I think the removal of total difficulty was also causing some of our readiness loggers to error. From interop channel on ETH R&D:

{"msg":"Unable to check genesis execution payload","level":"ERRO","ts":"2025-02-03T17:07:31.659060494Z","service":"slot_notifier","error":"ExecutionLayerGetBlockByNumberFailed(EngineError(Api { error: Json(Error("missing field totalDifficulty", line: 0, column: 0)) }))"}

It's cosmetic, but would be nice to fix (only relevant for devnets)