Hidden input disappears when value is emptied in Combobox vue

[AnnaYuS]

Not sure if it's a bug, but hidden input for html forms is not rendered if combobox is "nullable" and there is no selected value:
https://stackblitz.com/edit/vue-fhvdgs?file=src/App.vue

It seems like it should still be rendered. In case of a form with a single combobox there would be no named input field and the form would probably be invalid (at least that happens with a symfony form). Adding a hidden input manually works, so it's not a huge problem