Console error on public share auth page

When opening the share link asking for a password:

```
Cannot read properties of null (reading 'value')
```

https://github.com/nextcloud/text/blob/main/src/public.js#L51

https://juliushaertl.sentry.io/share/issue/c9a7f6638e6e460d8bb9868465713456/

