Convert m_micProximitySensorCanMute to new settings API

The `saveAudioSettings()` function lead to an infinite loop of
saving.

src/tabcontrollers/AudioTabController.h

@@ -71,7 +71,6 @@ private:
     int m_recordingDeviceIndex = -1;
     float m_micVolume = 1.0;
     bool m_micMuted = false;
-    bool m_micProximitySensorCanMute = false;
     bool m_micReversePtt = false;
     bool m_isDefaultAudioProfile = false;
     bool m_isPlaybackOverride = false;
@@ -129,7 +128,6 @@ public:
     void initStage2();
 
     void reloadAudioSettings();
-    void saveAudioSettings();
 
     void eventLoopTick();