title: React navigation undefined params
body: <p>I'm trying to pass params into a new screen, and implemented it like mentioned <a href="https://reactnavigation.org/docs/en/params.html" rel="noreferrer">here</a>.</p>
  
  <p><strong>I have the following <code>TouchableOpacity</code> button.</strong></p>
  
  <pre><code>&lt;TouchableOpacity
    onPress={() =&gt; {
      this.props.navigation.navigate('SomeScreen', {
        title: 'Title',
        subTitle: 'Subtitle',
      });
    }}
  &gt;
  </code></pre>
  
  <p><strong>On the other page (let's call it Somescreen), I have the following:</strong></p>
  
  <pre><code>render() {
    const { navigation } = this.props;
    const title = navigation.getParam('title');
  }
  </code></pre>
  
  <p>But <code>title</code> above is undefined: </p>
  
  <pre><code>{ params: undefined, routeName: "Somescreen", key: "id-xx" }
  </code></pre>
  
  <p><strong>My rootStack:</strong></p>
  
  <pre><code>const RootStack = createStackNavigator({
    SomescreenA: { screen: SomescreenA },
    SomescreenB: { screen: SomescreenB },
  }, { headerMode: 'none' });
  </code></pre>
  
  <p>Why are my params undefined in a new screen?</p>