Add missing require

This is most likely a bug in ActiveJob/Zeitwerk setup or something.

Author: solnic

sentry-rails/app/jobs/sentry/send_event_job.rb

@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 if defined?(ActiveJob)
+  require "active_job/base"
+
   module Sentry
     parent_job =
       if defined?(::ApplicationJob) && ::ApplicationJob.ancestors.include?(::ActiveJob::Base)