title: Set custom accessibilityIdentifier for GMSMarker
body: <p>I use a Google Maps Api for maps and markers.</p>
  
  <p>I enable accessibility for markers by setting: <code>mapView.accessibilityElementsHidden = false</code></p>
  
  <p>Now all my custom markers on map have accessibility ids like: <code>myappname.GMSPlaceMarker_somenumbers</code>, for example <code>myappname.GMSPlaceMarker_0x600000170200</code>.</p>
  
  <p>How could i set a one <code>accessibilityIdentifier</code> for all pins, for example <code>Map pin</code>?</p>
  
  <p>I already tried:</p>
  
  <ul>
  <li><code>marker.accessibilityLabel = "Map pin"</code> but it set <code>label</code> value, not <code>id</code></li>
  <li><code>marker.title = "Map pin"</code> nothing changes</li>
  <li><code>marker.setValue("Map pin", forKey: "accessibilityIdentifier")</code> nothing changes</li>
  </ul>
  
  <p>My <code>marker</code> is <code>let marker = GMSPlaceMarker()</code> where <code>class GMSPlaceMarker: GMSMarker</code></p>