Resolve Zarr v3 + fsspec/s3fs async aiohttp sessions unclosed after S3 reads/writes.

With the upgrade to Zarr v3, the storage layer from the older mostly synchronous/mapping-style store model to an async-backed store API. With S3, that means reads/writes go through fsspec/s3fs async machinery and can leave aiohttp sessions unclosed, causing noisy unclosed client session / connector warnings. No issue occurs from this at scale.