title: SLComposeViewController setInitialText not working on Twitter in iOS 11
body: <p>I am creating a <code>SLComposeViewController</code> of type <code>SLServiceTypeTwitter</code> and I'm adding an <code>url</code> and <code>text</code> to it. However, the text is not shown, only the <code>url</code>.</p>
  
  <p>Does anybody know why <code>SLComposeViewController's</code> <code>setInitialText</code> is not working on <code>Twitter</code> in <code>iOS 11</code>?</p>
  
  <p>Here is a snippet of my code:</p>
  
  <pre><code>SLComposeViewController *twPostSheet = [SLComposeViewController composeViewControllerForServiceType:SLServiceTypeTwitter];
  [twPostSheet setInitialText:copy];
  [twPostSheet addURL:[NSURL URLWithString:url]];
  
  UIViewController *controller = RCTPresentedViewController();
  twPostSheet.completionHandler = ^(SLComposeViewControllerResult result) {
      // Shared with success
  };
  [controller presentViewController:twPostSheet animated:YES completion:nil];
  </code></pre>