Ionic 5 Capacitor - Register push notification token after change in iOS settings

My code is set up as follows:

export class HomePage implements OnInit {

ngOnInit() {
    console.log('Initializing HomePage');

    // Request permission to use push notifications
    // iOS will prompt user and return if they granted permission or not
    // Android will just grant without prompting
    PushNotifications.requestPermission().then( result => {
      if (result.granted) {
        // Register with Apple / Google to receive push via APNS/FCM
        PushNotifications.register();
      } else {
        // Show some error
      }
    });

    // On success, we should be able to receive notifications
    PushNotifications.addListener('registration',
      (token: PushNotificationToken) => {
        alert('Push registration success, token: ' + token.value);
      }
    );

    // Some issue with our setup and push will not work
    PushNotifications.addListener('registrationError',
      (error: any) => {
        alert('Error on registration: ' + JSON.stringify(error));
      }
    );

    // Show us the notification payload if the app is open on our device
    PushNotifications.addListener('pushNotificationReceived',
      (notification: PushNotification) => {
        alert('Push received: ' + JSON.stringify(notification));
      }
    );

    // Method called when tapping on a notification
    PushNotifications.addListener('pushNotificationActionPerformed',
      (notification: PushNotificationActionPerformed) => {
        alert('Push action performed: ' + JSON.stringify(notification));
      }
    );
}

If the user denies permission on app first launch and then goes into the settings app and enables push notifications and then comes back to the app (without restarting the app) how do I access the registered token in this case? Do I need to register the token each time the app comes into the foreground as well as on app start? What is the recommended approach for an Ionic Capacitor app? Thanks!