Octree visualization without grid lines

Is it possible to visualize an octree without the grid lines? (I like them, but sometimes can mess the visualization). I searched on docs and in the cpp code but couldn't find anything to work.

I'm thinking in flag for the visualization, same idea as "show_normals" but "show_octree_node_lines" or something like this.

My first idea was to use `Octree.to_voxel_grid()` in order to visualize the same structure without the line set. However, this function is broken, as stated in #3269 .

If anyone knows how to do make this work, I can try to code and send a PR.

Thanks