DAL: remove dal attestations

What

Remove DAL attestation operations and adapt tests that use them.

Close #3115 (closed) and #4462 (closed).

Stacked on !11941 (merged).

Why

DAL attestation operations are not needed anymore and should not be used, as the DAL slots attestations are now included withing consensus attestations.

How

Just delete some code.

Manually testing the MR

Check CI