AudioIO does not depend directly on ControlToolBar ...

... use one more callback in the listener to change the ControlToolBar pause
state.

src/ProjectAudioManager.h

@@ -41,6 +41,7 @@ private:
    void OnAudioIOStopRecording() override;
    void OnAudioIONewBlockFiles(const AutoSaveFile & blockFileLog) override;
    void OnCommitRecording() override;
+   void OnSoundActivationThreshold() override;
 
    AudacityProject &mProject;