Penar Musaraj fa6aa7f627
FIX: Digest frequency issue on user creation
If `default email digest frequency` was set to "Never", users would get
a `digest_after_minutes` set to `nil` which triggered this error
in the logs if/when the site eventually changed that setting and
enabled digests:

```
NoMethodError (undefined method `>=' for nil:NilClass)
/var/www/discourse/app/mailers/user_notifications.rb:227:in `digest'
```
2020-06-01 17:39:16 -04:00
..