Incorrect Ed25519 public key validation

!NOTE The fix was released in v2.5.1 Reported by Arpit Jain @arpitjain099 via email. This validation gate misfires, allowing invalid public keys to be loaded. Full advisory: https://github.com/paragonie/sodiumcompat/security/advisories/GHSA-733q-f2wq-9c8w The actual downstream impact is minimal i...