Some config settings may be casted in hostPageSetting() in the annotator

Currently only the `openSidebar` setting is coerced, but other settings could be coerced for consistency. Some of these values may come from via in which case via will only produce string values.

from `annotator/config/index.js`

```
openSidebar: settings.hostPageSetting('openSidebar', {
allowInBrowserExt: true,
coerce: toBoolean,
}),
```

_Note. Some of the settings in are not actually used in the annotator and so there is no specific need to coerce them other than for consistency with `openSidebar` and with how they are coerced in `host-config.js` for the sidebar._