Remove unused fingerprint
Remove unused fingerprint

When running bundle exec brakeman -I:
```
...
...
1 fingerprint is unused:
9bf0691602eb033f80d35f6ee93736cace582ed9a28e35ca57057b649e3286db

Remove fingerprint?
yes
...
...
```

alphagov/frontend,alphagov/frontend,alphagov/frontend,alphagov/frontend