Fixed bug - no handleInstallError() was fired when Huawei Environment was not ready

[aberkowski]

There was a problem when onFailure() was fired with Exception other than IapApiException. No observer methods was fired (handleInstall() or handleInstallError()), so it was unknown that IAP was not installed. I had this problem when installing on fresh device without HMS Core installed. handleInstall() or handleInstallError() was not fired when user canceled HMS Core installation because throwned Exception was not instance of IapApiException