TLS client: Simplify cert's verification code (#5656)

Fixes https://github.com/XTLS/Xray-core/issues/5655

transport/internet/tls/pin.go

@@ -4,28 +4,8 @@ import (
 	"crypto/sha256"
 	"crypto/x509"
 	"encoding/hex"
-	"encoding/pem"
 )
 
-func CalculatePEMLeafCertSHA256Hash(certContent []byte) (string, error) {
-	var leafCert *x509.Certificate
-	for {
-		var err error
-		block, remain := pem.Decode(certContent)
-		if block == nil {
-			break
-		}
-		leafCert, err = x509.ParseCertificate(block.Bytes)
-		if err != nil {
-			return "", err
-		}
-		certContent = remain
-	}
-	certHash := GenerateCertHash(leafCert)
-	certHashHex := hex.EncodeToString(certHash)
-	return certHashHex, nil
-}
-
 // []byte must be ASN.1 DER content
 func GenerateCertHash[T *x509.Certificate | []byte](cert T) []byte {
 	var out [32]byte
@@ -37,3 +17,14 @@ func GenerateCertHash[T *x509.Certificate | []byte](cert T) []byte {
 	}
 	return out[:]
 }
+
+func GenerateCertHashHex[T *x509.Certificate | []byte](cert T) string {
+	var out [32]byte
+	switch v := any(cert).(type) {
+	case *x509.Certificate:
+		out = sha256.Sum256(v.Raw)
+	case []byte:
+		out = sha256.Sum256(v)
+	}
+	return hex.EncodeToString(out[:])
+}