title: Default spinner is not crescent but lines for Android Ionic 4
body: <p>I added ion-refresher in a Ionic 4 project like this :</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;ion-refresher slot="fixed"&gt;
      &lt;ion-refresher-content&gt;&lt;/ion-refresher-content&gt;
  &lt;/ion-refresher&gt;
  </code></pre>
  
  <p>But for Android platform the default spinner showing up is lines not crescent.</p>