Move the :fatal log setting into the SaaS config

This should only be set if the app is using the
rails-structured-logging gem, which means it should only be set in the
SAAS config. I think this is just something we missed in one of the
decoupling exercises we did.

saas/config/environments/production.rb

@@ -1,6 +1,9 @@
 Rails.application.configure do
   config.active_storage.service = :purestorage
+
+  # Enable structured logging, suppress unstructured log lines
   config.structured_logging.logger = ActiveSupport::Logger.new(STDOUT)
+  config.log_level = :fatal
 
   config.action_controller.default_url_options = { host: "app.fizzy.do", protocol: "https" }
   config.action_mailer.default_url_options     = { host: "app.fizzy.do", protocol: "https" }