Fix typo in RewardedVideoAdd sample (#927)
Fix typo in RewardedVideoAdd sample (#927)


firebase/flutterfire,firebase/flutterfire,firebase/flutterfire,firebase/flutterfire,firebase/flutterfire,firebase/flutterfire,googleads/googleads-mobile-flutter,firebase/flutterfire,googleads/googleads-mobile-flutter,googleads/googleads-mobile-flutter,firebase/flutterfire,firebase/flutterfire,firebase/flutterfire,googleads/googleads-mobile-flutter