Chore: Provide fixed attachment URLs for Channels (#4507)

Prior to this change, The attachment URL sent from Chatwoot to 3rd party integrations like Whatsapp and Facebook
involved a 301 redirect before the original content is served. This causes intermittent breakages for the sent attachments.

fixes: #3632
ref: https://blog.saeloun.com/2021/09/14/rails-7-adds-expiring-urls-to-active-storage.html

app/models/attachment.rb

@@ -44,12 +44,15 @@ class Attachment < ApplicationRecord
     base_data.merge(file_metadata)
   end
 
+  # NOTE: the URl returned does a 301 redirect to the actual file
   def file_url
     file.attached? ? url_for(file) : ''
   end
 
+  # NOTE: for External services use this methods since redirect doesn't work effectively in a lot of cases
   def download_url
-    file.attached? ? rails_storage_proxy_url(file) : ''
+    ActiveStorage::Current.host = Rails.application.routes.default_url_options[:host] if ActiveStorage::Current.host.blank?
+    file.attached? ? file.blob.url : ''
   end
 
   def thumb_url