Move num_failed_authentication_packets_received to QuicConnectionStats and fix QuicConnectionTest.IntegrityLimitDoesNotApplyWithoutDecryptionKey

QuicConnectionTest.IntegrityLimitDoesNotApplyWithoutDecryptionKey wasn't testing what it claimed since use_tagging_decrypter() had installed a decrypter at the ENCRYPTION_FORWARD_SECURE level.

PiperOrigin-RevId: 338760351
Change-Id: I33079112cb566bfcb54d81c46caa56f512b72267
diff --git a/quic/core/quic_connection_stats.cc b/quic/core/quic_connection_stats.cc
index 0cc6a73..d7440b4 100644
--- a/quic/core/quic_connection_stats.cc
+++ b/quic/core/quic_connection_stats.cc
@@ -56,6 +56,8 @@
   os << " sent_legacy_version_encapsulated_packets: "
      << s.sent_legacy_version_encapsulated_packets;
   os << " key_update_count: " << s.key_update_count;
+  os << " num_failed_authentication_packets_received: "
+     << s.num_failed_authentication_packets_received;
   os << " }";
 
   return os;