Fix quiche build error in GCC. No behavior change.

Address GCC error during Envoy import: enumerated and non-enumerated type in conditional expression [-Werror=extra]

PiperOrigin-RevId: 367245558
Change-Id: I0c71cf80336e24e72aa4d133f53b230e4e9d2471

quic/core/http/quic_spdy_session.cc

diff --git a/quic/core/http/quic_spdy_session.cc b/quic/core/http/quic_spdy_session.cc
index 8a4058c..37db9ac 100644
--- a/quic/core/http/quic_spdy_session.cc
+++ b/quic/core/http/quic_spdy_session.cc
@@ -472,8 +472,9 @@
                   supported_versions,
                   /*num_expected_unidirectional_static_streams = */
                   VersionUsesHttp3(connection->transport_version())
-                      ? kHttp3StaticUnidirectionalStreamCount
-                      : 0),
+                      ? static_cast<QuicStreamCount>(
+                            kHttp3StaticUnidirectionalStreamCount)
+                      : 0u),
       send_control_stream_(nullptr),
       receive_control_stream_(nullptr),
       qpack_encoder_receive_stream_(nullptr),