title: How to hide material input
body: <p>Normally if I want a form field to be included in the submission but not visible I do an <code>&lt;input type="hidden" /&gt;</code></p>
  
  <p>However, <code>matInput</code> doesn't allow for a type of <code>hidden</code>. I could use a <code>display: none;</code> but that usually excludes the value from submission.</p>
  
  <p>Is there a way to hide the input in a material dynamic form that also include the value in submission?</p>