Disable usage of csrf token in Rails

Rails UJS `.csrfToken` doesn't seem to overrideable. As it uses the same
methodlogy under the hood, we do not need to cache the CSRF token:

https://github.com/rails/rails/blob/master/actionview/app/assets/javascripts/rails-ujs/utils/csrf.coffee#L5-L8

app/assets/javascripts/lib/utils/rails_ujs.js

 import Rails from '@rails/ujs';
-import csrf from './csrf';
 
 export const initRails = () => {
   // eslint-disable-next-line no-underscore-dangle
@@ -18,7 +17,4 @@ export const initRails = () => {
   }
 };
 
-// use our cached token for any Rails-generated AJAX requests
-Rails.csrfToken = () => csrf.token;
-
 export { Rails };