Deprecate --gfe2_restart_flag_js_friendly_authenticated_request_headers

Flag verified and in prod since cl/707675981

Protected by deprecating flag.

PiperOrigin-RevId: 787139214

quiche/balsa/header_properties.cc

diff --git a/quiche/balsa/header_properties.cc b/quiche/balsa/header_properties.cc
index 17115b4..b0e7891 100644
--- a/quiche/balsa/header_properties.cc
+++ b/quiche/balsa/header_properties.cc
@@ -5,8 +5,6 @@
 
 #include "absl/container/flat_hash_set.h"
 #include "absl/strings/string_view.h"
-#include "quiche/common/platform/api/quiche_flag_utils.h"
-#include "quiche/common/platform/api/quiche_flags.h"
 #include "quiche/common/quiche_text_utils.h"
 
 namespace quiche::header_properties {