By default, use localized long date-time format

because ISO 8601 is not easy to the eye (at least for non-tech people).

client/config/blazeHelpers.js

@@ -47,7 +47,7 @@ Blaze.registerHelper('isTouchScreenOrShowDesktopDragHandles', () =>
 Blaze.registerHelper('moment', (...args) => {
   args.pop(); // hash
   const [date, format] = args;
-  return moment(date).format(format);
+  return moment(date).format(format ?? 'LLLL');
 });
 
 Blaze.registerHelper('canModifyCard', () =>