Improve generator logging and debugging

This commit is a follow-up to rails#49448, with regards to [this comment][].

Prior to this commit, logging and debugging for
[Rails::Generators::Actions][] was limited even when enabling
`RAILS_LOG_TO_STDOUT`. This was because the private `action` method in
the corresponding test was capturing `$stdout`.

[this comment]: rails#49448 (comment)
[Rails::Generators::Actions]: https://api.rubyonrails.org/v7.0.8/classes/Rails/Generators/Actions.html

Author: stevepolitodesign

railties/test/generators/actions_test.rb

@@ -720,7 +720,11 @@ def test_log_with_status_with_quiet
 
   private
     def action(...)
-      capture(:stdout) { generator.send(...) }
+      if ENV["RAILS_LOG_TO_STDOUT"] == "true"
+        generator.send(...)
+      else
+        capture(:stdout) { generator.send(...) }
+      end
     end
 
     def revoke(...)