refreshPushToken method
Manually re-fetch the current FCM token and re-upload it to the backend
if it has changed or the last upload is older than 24 hours. The SDK
calls this automatically on app launch, on foreground resume, and on
FirebaseMessaging.onTokenRefresh after enablePushEngagementTracking
has been called.
Implementation
Future<void> refreshPushToken() async {
await PushTokenRefresher.instance.refresh(this);
}