Sorting list by subscriber count throws error

**Version:**
 - listmonk: 4.0.1
 - OS: docker-image

**Description of the bug and steps to reproduce:**
When trying to sort all lists by "Subscribers" an error message is thrown: "Error fetching Lists: pq: column "subscriber_count" does not exist"

**Log:**
```
lists.go:51: error fetching lists: pq: column "subscriber_count" does not exist
```
