fix(pdp): fix ed25519 auth

[hannahhoward]

fix annoying bug - x509 does not parse to pointer type on ed25519

From the doc on x509.ParsePKIXPublicKey

// ParsePKIXPublicKey parses a public key in PKIX, ASN.1 DER form. The encoded
// public key is a SubjectPublicKeyInfo structure (see RFC 5280, Section 4.1).
//
// It returns a *[rsa.PublicKey], *[dsa.PublicKey], *[ecdsa.PublicKey],
// [ed25519.PublicKey] (not a pointer), or *[ecdh.PublicKey] (for X25519).
// More types might be supported in the future.
//
// This kind of key is commonly encoded in PEM blocks of type "PUBLIC KEY".