Fix: the generation of the skirt does not take the wipe_tower into account.

jira: STUDIO-10381
Change-Id: I523d366d6d569696de48f872be827d73710cb526
(cherry picked from commit 939b405c35809dbceb65e5efdc65622407065b65)

src/libslic3r/GCode/WipeTower.hpp

@@ -191,6 +191,7 @@ public:
     BoundingBoxf get_bbx() const {
         BoundingBox  box = get_extents(m_outer_wall.front());
         BoundingBoxf res = BoundingBoxf(unscale(box.min), unscale(box.max));
+        res.translate(m_rib_offset.cast<double>());
         return res;
     }
     Polylines get_outer_wall() const {