urlfilter.cgi: Fixes bug#10649 - calls urlfilterctrl with remove option if update...

urlfilter.cgi: Fixes bug#10649 - calls urlfilterctrl with remove option if update disabled

- When the url filter update enable checkbox is unchecked then this patch calls
   urlfilterctrl with the remove option added in the otrher patch of this series.
- Tested on my vm testbed that this change does remove the urlfilter symlink from the
   fcron directories when the update is disabled.

Fixes: Bug#10649
Tested-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>