Error when setting a placeholder on <pagefind-modal-trigger> in version 1.5.2

I get this error when trying to set the placeholder to anything, reactive vue prop or just simple static value:

```vue
    <pagefind-modal-trigger
              :placeholder="t('nav.search')"
            />
```

```
Failed setting prop "placeholder" on <pagefind-modal-trigger>: value Look is invalid. TypeError: Cannot set property placeholder of #<PagefindModalTrigger> which has only a getter
```