Disable QUICv2 for MASQUE

Most servers out there don't support QUICv2, let's drop it in MASQUE for now to avoid version negotiation round trips until we have support for compatible version negotiation.

Not flag protected because this version list is not used in production.

PiperOrigin-RevId: 525309232
diff --git a/quiche/quic/masque/masque_utils.cc b/quiche/quic/masque/masque_utils.cc
index 548f62b..b31eccb 100644
--- a/quiche/quic/masque/masque_utils.cc
+++ b/quiche/quic/masque/masque_utils.cc
@@ -17,8 +17,8 @@
   QuicVersionInitializeSupportForIetfDraft();
   ParsedQuicVersionVector versions;
   for (const ParsedQuicVersion& version : AllSupportedVersions()) {
-    // Use all versions that support IETF QUIC.
-    if (version.UsesHttp3()) {
+    // Use all versions that support IETF QUIC except QUICv2.
+    if (version.UsesHttp3() && !version.AlpnDeferToRFCv1()) {
       QuicEnableVersion(version);
       versions.push_back(version);
     }