title: Error: Namespace "iOS" does not exist in Unity.Notifications
body: <p>I added </p>
  
  <pre><code>using Unity.Notifications.Android;
  using Unity.Notifications.iOS;
  </code></pre>
  
  <p>to my script. </p>
  
  <p>VisualStudio says everything is fine, the intellisense sees fields from both namespaces fine, and I'm able to run in the editor fine.</p>
  
  <p>But then when I try to build for Android to test of my phone, it says the namespace iOS does not exist in Unity.Notifications.</p>
  
  <p>If I remove all iOS code it builds fine.</p>