Generate 500.html with assets:precompile, remove loading from Google Fonts (#5067)

lib/tasks/assets.rake

@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+if Rake::Task.task_defined?('assets:precompile')
+  Rake::Task['assets:precompile'].enhance do
+    html = ApplicationController.render('errors/500', layout: 'error')
+    File.write(Rails.root.join('public', '500.html'), html)
+  end
+end