fix(cellNav): focuser element should not have width or height or else the window will scroll to it in some situations

Author: swalters

src/features/cellnav/less/cellNav.less

@@ -9,3 +9,8 @@
   outline: 0;
   background-color: @focusedCell;
 }
+
+.ui-grid-focuser {
+  width:0px;
+  height:0px;
+}