title: onNotificationOpened method not getting called in react native firebase
body: <p>i am using react-native-firebase for notification in my react native project and i am trying to call onNotificationOpened and getInitialNotification from componentDidMount method but these two methods not getting called, any suggestion will be appreciated</p>
  
  <pre class="lang-js prettyprint-override"><code>this.removeNotificationOpenedListener = firebase.notifications().onNotificationOpened((notificationOpen: NotificationOpen) =&gt; {
      console.log('onNotificationOpened AppJS :', notificationOpen)
      const { action, notification } = notificationOpen
      let item = JSON.parse(notification.data.body)
      console.log('onNotificationOpened AppJS : body ', item)
  
      console.log('onNotificationOpened AppJS : action ', action)
  
  })
  
  firebase.notifications().getInitialNotification()
      .then((notificationOpen: NotificationOpen) =&gt; {
          if (notificationOpen) {
              console.log('getInitialNotification AppJS : Shoeb ########: ')
              // App was opened by a notification
              // Get the action triggered by the notification being opened
              const { action, notification } = notificationOpen
              let item = JSON.parse(notification.data.body)
              console.log('getInitialNotification AppJS : item ', item)
              console.log('getInitialNotification AppJS : action ', action)
  
          }
      })
  </code></pre>