title: Xamarin Forms Shell bind flyout icon theme aware
body: <p>I have a Xamarin Forms Shell Application with a flyout. My entries are defined like this:</p>
  <pre><code>&lt;FlyoutItem Title=&quot;{x:Static resources:Strings.DashboardTitle}&quot; FlyoutIcon=&quot;ic_dashboard_black&quot;&gt;
      &lt;Tab&gt;
          &lt;ShellContent&gt;
              &lt;dashboard:DashboardPage /&gt;
          &lt;/ShellContent&gt;
      &lt;/Tab&gt;
  &lt;/FlyoutItem&gt;
  </code></pre>
  <p>This works so far as the icons is shown. But to support light and dark theme I would like for example to be able to bind that with an AppThemeBinding. Is that possible? Or how would I theme the icons in the flyout?</p>