title: How do i make a TabNavigator button push a modal screen with React Navigation
body: <p>Using the React Navigation tab navigator <a href="https://reactnavigation.org/docs/navigators/tab" rel="noreferrer">https://reactnavigation.org/docs/navigators/tab</a> how do I make one of the tab buttons push the screen up as a full screen modal?  I see the stack navigator has a <code>mode=modal</code> option.  how do I get that mode to be used when clicking on the <code>TakePhoto</code> tab button?  Clicking on it currently still shows the tab bar on the bottom.</p>
  
  <pre><code>const MyApp = TabNavigator({
    Home: {
      screen: MyHomeScreen,
    },
    TakePhoto: {
      screen: PhotoPickerScreen, // how can I have this screen show up as a full screen modal?
    },
  });
  </code></pre>