lib/ui/taskexp: Fix missing Gtk import
Adding back gtk objects import.
Fix bug introduce when adding validation on gtk import.
Signed-off-by: David Khouya <dakhouya@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 765be5ef60668f8a1cfbcba248f4995725807196)
Signed-off-by: Steve Sakoman <steve@sakoman.com>