`GeometrySet::compute_boundbox_without_instances` may not initialize min
max in some cases such as meshes without vertices.
This can result in a Bounding Box with impossible dimensions
(min=FLT_MAX, max=-FLT_MAX).
So repeat the same solution seen in `BKE_object_boundbox_calc_from_mesh`
and set boundbox values to zero.
Reviewed By: HooglyBoogly
Differential Revision: https://developer.blender.org/D13664
1c7d7c9150