title: Mat Autocomplete not setting input value when used as a formControl
body: <p>I have a custom autocomplete component that implements <code>ControlValueAccessor</code>. From the parent component I am tying to set the value using <code>form.get('productName').setValue('Product 1');</code>. This sets the value in the form but it's not reflected in the input that is associated to the autocomplete.</p>
  <p>I have a stackblitz example that shows the input not displaying the value. As soon as I remove the attribute <code>[matAutocomplete]=&quot;auto&quot;</code> from the input, the value is visible in the UI.</p>
  <p><a href="https://stackblitz.com/edit/angular-autocomplete-form-control?file=src%2Fapp%2Fapp.component.ts" rel="nofollow noreferrer">https://stackblitz.com/edit/angular-autocomplete-form-control?file=src%2Fapp%2Fapp.component.ts</a></p>
  <p>I have tried what the mentioned here but no success either - <a href="https://stackoverflow.com/a/56073917/4142653">https://stackoverflow.com/a/56073917/4142653</a></p>