`null-e clean --dry-run` doesn't output expected information

Scan sub-command suggests that `null-e clean --dry-run` will preview what would be deleted and multiple similar dry-run commands will do this as well (e.g. `git clean -npx`).

Current (`0.2.0`) output is following, which is less than ideal

```
🤖 null-e Clean v0.2.0

Will clean 152 artifacts from 120 projects (12.58 GiB)


✓ Dry run complete. Would clean 12.58 GiB from 152 artifacts.
```