Removes the IsReadingListEnabled flags

ios/chrome/browser/ui/reading_list/BUILD.gn

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 bundle_data("resources") {
   sources = [
     "resources/distillation_fail.png",
     "resources/distillation_fail@2x.png",
     "resources/distillation_fail@3x.png",
     "resources/distillation_success.png",
@@ skipping 41 matching lines @@
     "reading_list_toolbar.h",
     "reading_list_toolbar.mm",
     "reading_list_view_controller.h",
     "reading_list_view_controller.mm",
   ]
   deps = [
     ":resources",
     "//base",
     "//components/prefs",
     "//components/reading_list/core",
-    "//components/reading_list/core:flags",
     "//components/reading_list/ios",
     "//components/strings",
     "//components/url_formatter",
     "//ios/chrome/app/strings",
     "//ios/chrome/browser",
     "//ios/chrome/browser/browser_state",
     "//ios/chrome/browser/favicon",
     "//ios/chrome/browser/reading_list",
     "//ios/chrome/browser/tabs",
     "//ios/chrome/browser/ui",
@@ skipping 72 matching lines @@
     "//ios/testing/earl_grey:earl_grey_support",
     "//ios/third_party/earl_grey",
     "//ios/third_party/material_components_ios",
     "//ios/web:test_support",
   ]
   libs = [
     "UIKit.framework",
     "XCTest.framework",
   ]
 }