Alpha/DAL: acusations contain the lag index
On top of !20783 (merged).
This MR adds a lag_index field to DAL accusations. This field is needed in order to point to the trap referred to by the accusation when this refers to an attestation operation with a DAL payload containing DAL attestations for several published levels. (That is, when there is more than one attestation lag.)
Edited by Guillaume Genestier