use rails storage proxy for audit log url

app/models/submission.rb

@@ -72,7 +72,9 @@ class Submission < ApplicationRecord
   }, scope: false, prefix: true
 
   def audit_trail_url
-    audit_trail&.url
+    return if audit_trail.blank?
+
+    Rails.application.routes.url_helpers.rails_storage_proxy_url(audit_trail, **Docuseal.default_url_options)
   end
   alias audit_log_url audit_trail_url
 end