Merge pull request rails#53461 from y-yagi/follow_up_53444

Correctly check whether Action Cable is enabled in `AuthenticationGenerator`

Author: rafaelfranca

railties/lib/rails/generators/rails/authentication/authentication_generator.rb

@@ -19,7 +19,7 @@ def create_authentication_files
         template "app/controllers/concerns/authentication.rb"
         template "app/controllers/passwords_controller.rb"
 
-        template "app/channels/application_cable/connection.rb" unless options.skip_action_cable?
+        template "app/channels/application_cable/connection.rb" if defined?(ActionCable::Engine)
 
         template "app/mailers/passwords_mailer.rb"
 

railties/test/generators/authentication_generator_test.rb

@@ -108,11 +108,14 @@ def test_model_test_is_skipped_if_test_framework_is_given
   end
 
   def test_connection_class_skipped_without_action_cable
-    generator([destination_root], skip_action_cable: true)
-
+    old_value = ActionCable.const_get(:Engine)
+    ActionCable.send(:remove_const, :Engine)
+    generator([destination_root])
     run_generator_instance
 
     assert_no_file "app/channels/application_cable/connection.rb"
+  ensure
+    ActionCable.const_set(:Engine, old_value)
   end
 
   private