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

config/environments/test.rb

@@ -20,8 +20,8 @@ Rails.application.configure do
   config.public_file_server.headers = {
     'Cache-Control' => "public, max-age=#{1.hour.to_i}"
   }
-  config.action_mailer.default_url_options = { host: 'localhost', port: 3000 }
-  Rails.application.routes.default_url_options = { host: 'localhost', port: 3000 }
+  config.action_mailer.default_url_options = { host: 'http://localhost:3000' }
+  Rails.application.routes.default_url_options = { host: 'http://localhost:3000' }
 
   # Show full error reports and disable caching.
   config.consider_all_requests_local       = true