Replace client side TLS 0-RTT flag with protocol flag FLAG_quic_disable_tls_zero_rtt.

PiperOrigin-RevId: 338543748
Change-Id: Iab3cc2e2787dfe22008576d16ed6dcc5b68c5166

quic/core/crypto/quic_crypto_client_config.cc

diff --git a/quic/core/crypto/quic_crypto_client_config.cc b/quic/core/crypto/quic_crypto_client_config.cc
index a7e4f49..c54c5d3 100644
--- a/quic/core/crypto/quic_crypto_client_config.cc
+++ b/quic/core/crypto/quic_crypto_client_config.cc
@@ -68,7 +68,7 @@
     : proof_verifier_(std::move(proof_verifier)),
       session_cache_(std::move(session_cache)),
       ssl_ctx_(TlsClientConnection::CreateSslCtx(
-          GetQuicRestartFlag(quic_enable_zero_rtt_for_tls_v2))) {
+          !GetQuicFlag(FLAGS_quic_disable_client_tls_zero_rtt))) {
   DCHECK(proof_verifier_.get());
   SetDefaults();
 }