title: Change accessibility focus in react-native app on drawer/modal open
body: <p>I'm trying to improve accessibility on a react native app and am facing the following problem: when the user opens the menu drawer, the focus doesn't change to the modal drawer content. Instead swiping left and right focuses content that's in the background.</p>
  
  <p>I have tried setting dynamic accessibility props to the drawer and main content area:</p>
  
  <pre><code>&lt;NavigationMenu
      importantForAccessibility={isNavigationVisible ? 'yes' : 'no-hide-descendants'}
  /&gt;
  &lt;DashboardContent
      importantForAccessibility={isNavigationVisible ? 'no-hide-descendants' : 'yes'}
  /&gt;
  </code></pre>
  
  <p>Where <code>isNavigationVisible</code> is a prop that gets updated when the drawer opens, but this had no effect.</p>
  
  <p>Is there any way to force the focus change to the drawer when it opens?</p>