Error that can occur when selected profile is wholly covered by PRONOM

If you use a collection profile that is covered by PRONOM, it works okay, and then you can de-select 'First use PRONOM' and get some meaningful results.

But if you then re-select 'First use PRONOM', it goes ☠️ and says

```
RuntimeError: node.querySelectorAll is not a function
```

in a few places!