Remove time zone preservation

This was introduced in the rails 8.0 upgrade because of deprecation
warnings. Without the new default file we no longer get the warnings
so i've removed the line from the application config.

config/application.rb

@@ -38,7 +38,5 @@ class Application < Rails::Application
 
     # Don't generate system test files.
     config.generators.system_tests = nil
-
-    Rails.application.config.active_support.to_time_preserves_timezone = :zone
   end
 end