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

app/models/channel/telegram.rb

@@ -95,7 +95,7 @@ class Channel::Telegram < ApplicationRecord
       when 'file'
         telegram_attachment[:type] = 'document'
       end
-      telegram_attachment[:media] = attachment.file_url
+      telegram_attachment[:media] = attachment.download_url
       telegram_attachments << telegram_attachment
     end
 

app/models/channel/whatsapp.rb

@@ -85,7 +85,7 @@ class Channel::Whatsapp < ApplicationRecord
   def send_attachment_message(phone_number, message)
     attachment = message.attachments.first
     type = %w[image audio video].include?(attachment.file_type) ? attachment.file_type : 'document'
-    attachment_url = attachment.file_url
+    attachment_url = attachment.download_url
     response = HTTParty.post(
       "#{api_base_path}/messages",
       headers: api_headers,