fix(bolt-boost): current slot logic

[thedevbirb]

This PR adds some of the missing steps in the get_header_with_proofs function that are present in the get_header wrapper in Commit-Boost.

In particular, it adds the following line:

    state.get_or_update_slot_uuid(params.slot);

that updates the local current slot when the beacon client calls this function. That was missing and causing some errors when submitting constraints because they were considered too far in the future.