[gstreamer] Listen to FOCUS_MOVE message and send caf-update messages. Fixes JB#7977
[gstreamer] Listen to FOCUS_MOVE message and send caf-update messages. Fixes JB#7977

sailfishos/gst-droidcamsrc,sailfishos/gst-droidcamsrc,sailfishos/gst-droidcamsrc