Update detectInteraction documentation am: 46816afa

     * 1) Any face is detected and the framework is notified via

     *    ISessionCallback#onInteractiondetected

     * 2) The operation was cancelled by the framework (see ICancellationSignal)

     * 3) An error occurred, for example ERROR::TIMEOUT

     *

     * Note that if the operation is canceled, the implementation must notify the framework via

     * ISessionCallback#onError with Error::CANCELED.