selectize options ignore language strings

when naming selectize options with a language string, it’s not displayed as it should.

in this example, `THEME_X.SELECT_OPTION1` doesn’t render the corresponding string from the `languages.yaml` file, instead it appears exactly as “THEME_X.SELECT_OPTION1”.
```yaml
form.field:
type: selectize
selectize:
options:
- text: THEME_X.SELECT_OPTION1
value: option1
```

needless to say i made sure the string was in the theme’s `languages.yaml`.

The report points to selectize field options and the theme's languages.yaml; start by tracing how the admin plugin resolves option labels before Selectize renders them. Reproduce with the supplied form.field configuration, then verify that THEME_X.SELECT_OPTION1 displays its translated value rather than the key.

Written by the indexing model from the issue text.