FIX: gracefully deal with lack of field label for dropdown and add settings explanation key value

assets/javascripts/wizard/initializers/custom.js.es6

@@ -28,7 +28,7 @@ export default {
       isFlagSelector() {
           const field = this.get('field');
           //TODO improve the way this detects a flag dropdown (currently it relies on the string 'Nation', e.g. 'Nationality' or 'National Flag' appearing in label)
-          return (field.label.includes(Discourse.SiteSettings.wizard_national_flags_label_cue)) ?  true :  false;
+            return  (typeof field.label !== 'undefined') ? (field.label.includes(Discourse.SiteSettings.wizard_national_flags_label_cue)) ?  true :  false : false;
         }
     });
 

config/locales/server.en.yml

@@ -23,3 +23,4 @@ en:
   site_settings:
     wizard_redirect_exclude_paths: "Routes excluded from wizard redirects."
     wizard_recognised_image_upload_formats: "File types which will result in upload displaying an image preview"
+    wizard_national_flags_label_cue: "The characters that must appear in the dropdown field label for it to show a flag"