Use `IsIetfQuic()` instead of the deprecated `UsesHttp3()`.

PiperOrigin-RevId: 836844411

quiche/quic/core/quic_utils.cc

diff --git a/quiche/quic/core/quic_utils.cc b/quiche/quic/core/quic_utils.cc
index 36ea172..cd18fb1 100644
--- a/quiche/quic/core/quic_utils.cc
+++ b/quiche/quic/core/quic_utils.cc
@@ -601,7 +601,7 @@
 
 bool IsValidWebTransportSessionId(WebTransportSessionId id,
                                   ParsedQuicVersion version) {
-  QUICHE_DCHECK(version.UsesHttp3());
+  QUICHE_DCHECK(version.IsIetfQuic());
   return (id <= std::numeric_limits<QuicStreamId>::max()) &&
          QuicUtils::IsBidirectionalStreamId(id, version) &&
          QuicUtils::IsClientInitiatedStreamId(version.transport_version, id);