Zarr v2 vs. v3

[davramov]

An interesting bug has appeared with the itk-vtk-viewer/tiled app at 8.3.2, where the metadata is saved as both the v2 and v3 versions of the Zarr specification.

This is problematic because

• When ingesting, Tiled will select the v3 spec to serve
• itk-vtk-viewer is built for the v2 spec

I found a workaround where we can delete the v3 spec (zarr.json). It is also strange, because looking at fresh reconstructions from NERSC, I don't always see the zarr.json file until after I copy into the example_samples folder that Tiled watches. It makes me wonder when/where the v3 spec is generated.