hasAd method
Returns 'true' if there is an ad loaded for this placementId.
Implementation
Future<bool> hasAd() async {
  try {
    return AatkitFlutterPluginPlatform.instance.hasAdForAppOpenAd(name);
  } on PlatformException catch (e) {
    aatkitLog("PlatformException, error: $e");
    return false;
  }
}