Restore pin for Rails 7.0

Author: JonRowe

example_app_generator/spec/support/default_preview_path

@@ -52,7 +52,7 @@ require_file_stub 'config/environment' do
           config.action_mailer.show_previews = (ENV['SHOW_PREVIEWS'] == 'true')
         end
 
-        config.active_record.legacy_connection_handling = false
+        config.active_record.legacy_connection_handling = false if Rails::VERSION::STRING.start_with?('7.0')
       end
     end