FIX: Make disabling TLS in mail possible again

Following the Rails 7 upgrade, the `DISCOURSE_SMTP_ENABLE_START_TLS`
setting doesn’t work anymore. This is because Rails upgraded the
`net-smtp` gem to the 0.3.1 version which enables `starttls` by default.
The `mail` gem doesn’t support this new behavior yet and doesn’t know
how to disable TLS. This should be fixed in an upcoming release.

Meanwhile applying this patch allows us to get back the previous
behavior which is expected by many.

config/environments/production.rb

@@ -41,7 +41,7 @@ Discourse::Application.configure do
       settings[:tls] = true
     end
 
-    config.action_mailer.smtp_settings = settings.reject { |_, y| y.nil? }
+    config.action_mailer.smtp_settings = settings.compact
   else
     config.action_mailer.delivery_method = :sendmail
     config.action_mailer.sendmail_settings = { arguments: '-i' }