Merge branch 'aa-add-subscription-history-comment' into 'master'

Add subscription history creation comment

See merge request gitlab-org/gitlab!57206

ee/app/models/gitlab_subscription_history.rb

 # frozen_string_literal: true
 
+# GitlabSubscriptionHistory records the previous value before change.
+# `gitlab_subscription_created` is not used. Because there is no previous value before creation.
 class GitlabSubscriptionHistory < ApplicationRecord
   enum change_type: [:gitlab_subscription_created,
                      :gitlab_subscription_updated,