Removes the IsReadingListEnabled flags

ios/chrome/browser/experimental_flags.mm

Index: ios/chrome/browser/experimental_flags.mm
diff --git a/ios/chrome/browser/experimental_flags.mm b/ios/chrome/browser/experimental_flags.mm
index 6d6ef70869e297a6b65e20bbaf55f225a8965129..0e11adbbbca719d7e84455c37b2aed00e5376340 100644
--- a/ios/chrome/browser/experimental_flags.mm
+++ b/ios/chrome/browser/experimental_flags.mm
@@ -17,7 +17,6 @@
 #include "base/strings/string_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "components/autofill/core/common/autofill_switches.h"
-#include "components/reading_list/core/reading_list_switches.h"
 #include "components/variations/variations_associated_data.h"
 #include "ios/chrome/browser/chrome_switches.h"
 #include "ios/web/public/web_view_creation_util.h"
@@ -219,10 +218,6 @@ bool IsReaderModeEnabled() {
       switches::kEnableReaderModeToolbarIcon);
 }
 
-bool IsReadingListEnabled() {
-  return reading_list::switches::IsReadingListEnabled();
-}
-
 bool IsSafariVCSignInEnabled() {
   return ![[NSUserDefaults standardUserDefaults]
       boolForKey:kSafariVCSignInDisabled];