Merge branch 'default-gitlab-hosts' into 'master'

Update the gitlab_host light setting to match the defaults

Closes #33360

See merge request gitlab-org/gitlab!18091

config/light_settings.rb

@@ -22,7 +22,7 @@ class LightSettings
     end
 
     def host
-      config['gitlab']['host']
+      config.dig('gitlab', 'host') || ENV['GITLAB_HOST'] || 'localhost'
     end
 
     def gl_subdomain?