There isn't a built-in helper for that, but you can do something like this in your expression:
= Math.floor($helpers.rand() * (max - min + 1)) + min;
max is the maximum value that the random number should take and
min is the minimum value.
Note that you can build your own helper if you are planning to use this expression multiple times. Here's a blog post that details how to do it: https://www.haikuforteams.com/blog/helper-functions/