Update onoff_widget.xml

small change 
new interface since we have an ui that is almost useless
we does not need an 1x1 widget without feedback (text), we should use an widget with 4x1 or 4x2 with all features (multi profile(on/off) and text 
<appwidget-provider ends up with /> and not /appwidget>
this also fix update period after widget toogle