Update SignalTransition API to avoid relying on injected signal parameters

import QtQuick
import QtQuick.Controls.Basic
import QtQml.StateMachine as DSM

Window {
    width: 640
    height: 480
    visible: true

    Button {
        id: button
        text: "Quit"
        // define the signal the SignalTransition is connected with
        signal mysignal(mystr: string)
        // on clicking the button emit the signal with a single string argument
        onClicked: button.mysignal("test")
    }
    DSM.StateMachine {
        id: stateMachine
        initialState: state
        running: true
        DSM.State {
            id: state
            DSM.SignalTransition {
                targetState: finalState
                signal: button.mysignal
                guard: mystr === "test"
            }
        }
        DSM.FinalState {
            id: finalState
        }
        onFinished: Qt.quit()
    }
}