Validates a 0x8009 account identity proof carried on a KeyPackage: rejects an explicit
expectedCiphersuite mismatch, a legacy 0xf2f1 or 0x8009 entry at the KeyPackage
level (PROOF-05), then validates the embedded LeafNode using the KeyPackage's own
ciphersuite (D-16 — never a caller-supplied "current" ciphersuite).
Validates a
0x8009account identity proof carried on a KeyPackage: rejects an explicitexpectedCiphersuitemismatch, a legacy0xf2f1or0x8009entry at the KeyPackage level (PROOF-05), then validates the embedded LeafNode using the KeyPackage's own ciphersuite (D-16 — never a caller-supplied "current" ciphersuite).