placeHolder is not rendered for items in Multiple Text questions

[andrewtelnov]

On loading the json like this:

{
    elements: [
      {
        type: "multipletext", name: "q1",
        items: [
          { name: "item1", placeHolder: "place holder" }
        ]
      }
    ]
  }

text question "renderedPlaceHolder" is not updated and equals to undefined.