fix(overlay): Make the overlays on top of everything

css/_variables.scss

 $tooltipsZ: 401;
 $dropdownMaskZ: 900;
 $dropdownZ: 901;
-$overlayZ: 902;
 $jitsipopoverZ: 1010;
 $centeredVideoLabelZ: 1011;
 $notificationZ: 1012;
 $popoverZ: 1015;
+$overlayZ: 1016;
 
 
 /**