Add compatibility for have_enqueued_mail (rails 7)

1. ActionMailer::DeliveryJob does not exist anymore
2. ActionMailer::Parameterized::DeliveryJob

According to my research they have both been superseeded by ActionMailer::MailDeliveryJob

Closes rspec#2531

Author: mhenrixon

lib/rspec/rails/matchers/have_enqueued_mail.rb

@@ -131,11 +131,13 @@ def mail_job_message(job)
         end
 
         def legacy_mail?(job)
-          job[:job] <= ActionMailer::DeliveryJob
+          defined?(ActionMailer::DeliveryJob) && job[:job] <= ActionMailer::DeliveryJob
         end
 
         def parameterized_mail?(job)
-          RSpec::Rails::FeatureCheck.has_action_mailer_parameterized? && job[:job] <= ActionMailer::Parameterized::DeliveryJob
+          base_mailer = defined?(ActionMailer::Parameterized::DeliveryJob) ? ActionMailer::Parameterized::DeliveryJob : ActionMailer::MailDeliveryJob
+          
+          RSpec::Rails::FeatureCheck.has_action_mailer_parameterized? && job[:job] <= base_mailer
         end
 
         def unified_mail?(job)