OME-Zarr output should write consolidated metadata

[carsten-jahn]

In data_utils/ome.py, the functions rgb_img_to_ome_zarr and multiplex_img_to_ome_zarr write a zarr-formatted image.

Both functions could consolidate the zarr metadata by adding the line

zarr.consolidate_metadata(z_root.store)

at the end of the function.

I don't know if there are any drawbacks. But this change would make the zarr output compatible which image readers that assume consolidated metadata exists.