title: Styling the searchbar in wix's react-native-navigation v2
body: <p>I'm using the search bar in a react-native app (iOS 11+).</p>
  
  <p>These are the options I gave to my screen:</p>
  
  <pre><code>options: {
      topBar: {
          title: {
              text: 'MyTitle',
              testID: TOP_APPS_ID,
          },
         searchBar: true,
         searchBarHiddenWhenScrolling: true,
      },
  },
  </code></pre>
  
  <p>And it does display the search bar:</p>
  
  <p><a href="https://i.stack.imgur.com/b6Rd0.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/b6Rd0.png" alt="enter image description here"></a></p>
  
  <p>However, I would like to remove the bottom border it adds by default. </p>
  
  <p>How can I achieve this? I tried setting "noBorder" to true in the topBar options but it still shows the border.</p>