Remove the export kml button in IE9

Fix for https://github.com/geoadmin/mf-geoadmin3/issues/1866

(IE9 does not support file save functionality and thus can't export kml. Note however, that a drawing can be send by email in the feedback tool)
Didn't work without it, because we use the `>` operator. If we used the `==` or `!=` operators, it would work.