Add parentPreconfirmationHash to preconf struct

[linoscope]

We added a new parentPreconfirmationHash field to the preconf struct here: https://github.com/NethermindEth/Catalyst/pull/747/files

This was to simplify the node sync process.

We must adjust our slashing logic to accomodate to this change.

[dantaik]

@linoscope triage check 👋 — trying to move this one forward.

This tracks adjusting our slashing logic for the new parentPreconfirmationHash field (Catalyst PR #747). Has the slashing logic been updated accordingly, or is this still pending?

Close it, or keep open?