FEATURE: admin can disable flags (#27171)

UI for admins to disable system flags.

app/controllers/admin/admin_controller.rb

@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 class Admin::AdminController < ApplicationController
+  include WithServiceHelper
+
   requires_login
   before_action :ensure_admin
 

app/controllers/admin/config/flags_controller.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+class Admin::Config::FlagsController < Admin::AdminController
+  def toggle
+    with_service(ToggleFlag) do
+      on_success do
+        Discourse.request_refresh!
+        render(json: success_json)
+      end
+      on_failure { render(json: failed_json, status: 422) }
+      on_model_not_found(:message) { raise Discourse::NotFound }
+      on_failed_policy(:invalid_access) { raise Discourse::InvalidAccess }
+      on_failed_contract do |contract|
+        render(json: failed_json.merge(errors: contract.errors.full_messages), status: 400)
+      end
+    end
+  end
+
+  def index
+  end
+end

app/controllers/admin/staff_controller.rb

@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 class Admin::StaffController < ApplicationController
+  include WithServiceHelper
+
   requires_login
   before_action :ensure_staff
 end