[Feature] Revive additional subdag verification

[vicsn]

🚀 Feature

See:
#2615
#2645

[raychu86]

The issue is explained here - https://github.com/ProvableHQ/snarkVM/pull/2615/files#r1991933662.

It was a sort of "off-by-one" error, where the author of the certificate was accidentally not included as part of the quorum calculation.

[acoglio]

I got "duped" into that too. I had to push a patch to ProvableHQ/snarkOS#3537. I propose to rename BatchCertificate::signatures() to BatchCertificate::endorsements().