Remove hardcoded crosshairs from brainsprite

[tsalo]

Summary

It would be great to remove the green and blue lines/planes from the brainsprite (see below).

Additional details

Improved visualization.

Next steps

I think this will require modification of the workbench scene file(s), which I do not have the expertise to do.

[tsalo]

@madisoth is there anyone in the DCAN lab who can do this?

[tsalo]

The original scene files shared by the DCAN team were massive (~200 MB I believe) and wouldn't fit well into the GitHub repo, so when I originally switched from the brainsprite code to using wb_command I ended up manually going through those files and removing anything that was modality (T1w vs. T2w) or slice-specific, which dramatically reduced the size of the files. If possible, it would be great to retain that change in the modified files.

One trick might be to modify the original scene files and share those, and then I could do a diff between the original and modified versions to see what changes actually fixed the crosshair issue. I could then isolate those changes and copy them over to the reduced scene file that's in the repo.