Bugfix/div as widget in form

considering this solid-form:

<solid-form id='myForm'
  data-src="data/list/user-1.jsonld"
  fields="first_name, last_name, username"
  widget-username="div"
></solid-form>

when we call myForm.getFormValue() instead of getting an error (cause div doesn't have name property) I now get all other values:

{
  "@id": "data/list/user-1.jsonld",
  "first_name": "John",
  "last_name": "Doe"
}