Fix some rotation-related issues (#3890)

* Fix issue with max_z after rotation

* Don't use `object.bounding_box()`, use `bounding_box_exact()` instead.

* Fix auto-orient

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Co-authored-by: SoftFever <softfeverever@gmail.com>

src/slic3r/GUI/Jobs/OrientJob.cpp

@@ -238,6 +238,7 @@ orientation::OrientMesh OrientJob::get_orient_mesh(ModelInstance* instance)
 
     om.setter = [instance](const OrientMesh& p) {
         instance->rotate(p.rotation_matrix);
+        instance->get_object()->invalidate_bounding_box();
         instance->get_object()->ensure_on_bed();
     };
     return om;