wal: Consensus WAL must store received certificates #1445
Description
Some inputs produced by the synchronization protocol (SyncValueResponse, which includes a CommitCertificate) and by the liveness protocol (PolkaCertificate and RoundCertificate) are currently not persisted to the consensus WAL.
They are all Certificates, namely types that aggregate multiple Vote inputs. While some of most of the included Vote inputs are likely duplicated (already received as single Vote inputs), the new Vote inputs must be persisted to the WAL.
The risk of not persisting, therefore not replaying those inputs upon recovery, is an inconsistent behaviour upon recovery.
Unfortunately, this is not easy to test.