Do not add routes when actions are not specified

Since #30241, if namepsace is specified, routes will be generated even
if there is no actions.

However, it seems that this behavior is not intentionally added behavior.
As with 5.1, routes should not be generated if actions are not specified.

Fixes #32072.

railties/lib/rails/generators/rails/controller/controller_generator.rb

@@ -16,6 +16,7 @@ def create_controller_files
 
       def add_routes
         return if options[:skip_routes]
+        return if actions.empty?
         route generate_routing_code
       end
 

railties/test/generators/controller_generator_test.rb

@@ -109,4 +109,11 @@ def test_namespaced_routes_with_multiple_actions_are_created_in_routes
       assert_match(/^  namespace :admin do\n    get 'dashboard\/index'\n    get 'dashboard\/show'\n  end$/, route)
     end
   end
+
+  def test_does_not_add_routes_when_action_is_not_specified
+    run_generator ["admin/dashboard"]
+    assert_file "config/routes.rb" do |routes|
+      assert_no_match(/namespace :admin/, routes)
+    end
+  end
 end