Remove obsolete backport from Rails 7 (#26254)

config/application.rb

@@ -46,7 +46,6 @@ require_relative '../lib/chewy/strategy/bypass_with_warning'
 require_relative '../lib/webpacker/manifest_extensions'
 require_relative '../lib/webpacker/helper_extensions'
 require_relative '../lib/rails/engine_extensions'
-require_relative '../lib/action_controller/conditional_get_extensions'
 require_relative '../lib/active_record/database_tasks_extensions'
 require_relative '../lib/active_record/batches'
 require_relative '../lib/simple_navigation/item_extensions'

lib/action_controller/conditional_get_extensions.rb

@@ -1,15 +0,0 @@
-# frozen_string_literal: true
-
-module ActionController
-  module ConditionalGetExtensions
-    def expires_in(*)
-      # This backports a fix from Rails 7 so that a more private Cache-Control
-      # can be overriden by calling expires_in on a specific controller action
-      response.cache_control.delete(:no_store)
-
-      super
-    end
-  end
-end
-
-ActionController::ConditionalGet.prepend(ActionController::ConditionalGetExtensions)