Skip Action Mailbox for No AR example app

Action Mailbox requires Active Record

Author: pirj

example_app_generator/generate_action_mailer_specs.rb

@@ -31,6 +31,7 @@
   if skip_active_record?
     comment_lines 'spec/support/default_preview_path', /active_record/
     comment_lines 'spec/support/default_preview_path', /active_storage/
+    comment_lines 'spec/support/default_preview_path', /active_mailbox/
   end
   copy_file 'spec/verify_mailer_preview_path_spec.rb'
 end

example_app_generator/spec/support/default_preview_path

@@ -29,6 +29,7 @@ require_file_stub 'config/environment' do
     if Rails::VERSION::STRING >= '6'
       require "action_cable/engine"
       require "active_job/railtie"
+      require "action_mailbox/engine"
     end
 
     # Require the gems listed in Gemfile, including any gems