Remove GFE verification from 5 protocol feature flags:
  gfe2_reloadable_flag_fix_http2_header_value_validation
  gfe2_reloadable_flag_quic_flush_pending_frames_and_padding_bytes_on_migration
  gfe2_reloadable_flag_tcp_proxy_dos_allow_non_blocking_actions
  gfe2_restart_flag_quic_no_common_cert_set
  gfe2_restart_flag_external_dos_for_cloud_tcp_proxy

To be reverted once the protocol freeze ends.

PiperOrigin-RevId: 420750601

quic/core/quic_flags_list.h

diff --git a/quic/core/quic_flags_list.h b/quic/core/quic_flags_list.h
index 988b6a2..a700fd7 100644
--- a/quic/core/quic_flags_list.h
+++ b/quic/core/quic_flags_list.h
@@ -72,7 +72,7 @@
 // If true, do not re-arm PTO while sending application data during handshake.
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_donot_rearm_pto_on_application_data_during_handshake, true)
 // If true, do not use the gQUIC common certificate set for certificate compression.
-QUIC_FLAG(FLAGS_quic_restart_flag_quic_no_common_cert_set, true)
+QUIC_FLAG(FLAGS_quic_restart_flag_quic_no_common_cert_set, false)
 // If true, drop unsent PATH_RESPONSEs and rely on peer\'s retry.
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_drop_unsent_path_response, true)
 // If true, enable server retransmittable on wire PING.