BUG: Fix empty Group nodes lacking a "consolidated_metadata" field#3967

TomAugspurger merged 3 commits into

zarr-developers:mainzarr-developers/zarr-python:mainfrom

TomAugspurger:tom/consolidated-metadata-leaf-node-fixTomAugspurger/zarr-python:tom/consolidated-metadata-leaf-node-fixCopy head branch name to clipboard