fix: load omero metadata for NGFF 0.5 data

[krokicki]

This PR fixes #959 which prevents transitional OMERO metadata from being correctly loaded for NGFF 0.5.

Previously parseOmeMetadata read multiscales from either attrs.ome.multiscales (v0.5+) or attrs.multiscales (≤v0.4), but always read omero from attrs.omero. As a result, channel rendering metadata (colors, windows, labels) was silently dropped for OME-Zarr 0.5 datasets.

This PR mirrors the existing multiscales pattern for omero.

@StephanPreibisch @mkitti

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[chrisj]

Thanks @krokicki

I think we can clean this section now by using something like

  const {ome} = attrs;
  const metadata = attrs.ome ?? attrs; // >0.4
  const { multiscales, omero } = metadata;

Unfortunately version is not as simple