Add error_details when the QuicCryptoServerConfig fails to get crypto proof.

net/quic/core/crypto/quic_crypto_server_config.cc

Index: net/quic/core/crypto/quic_crypto_server_config.cc
diff --git a/net/quic/core/crypto/quic_crypto_server_config.cc b/net/quic/core/crypto/quic_crypto_server_config.cc
index 3e230d31564fb382b90b75961430378ead8377b8..b896998c0ae73b991c2c44d7b84147aa862ab0ea 100644
--- a/net/quic/core/crypto/quic_crypto_server_config.cc
+++ b/net/quic/core/crypto/quic_crypto_server_config.cc
@@ -764,7 +764,7 @@ void QuicCryptoServerConfig::ProcessClientHello(
                                  primary_config->serialized, version, chlo_hash,
                                  &crypto_proof->chain, &crypto_proof->signature,
                                  &crypto_proof->cert_sct)) {
-      helper.Fail(QUIC_HANDSHAKE_FAILED, "");
+      helper.Fail(QUIC_HANDSHAKE_FAILED, "Missing or invalid crypto proof.");
       return;
     }
   }