Fix to issue #1375 to make it also zarr v3 compatible

[felixS27]

This is the fix to make the code for distributed cellpose also zarr v3 compatible.
As it is mentioned in issue #1375

[mrariden]

The issue is that people still have zarr v2 arrays. Ideally, we'd have a way to support both. This solution doesn't appear to be backwards compatible.

Although you'd have to juggle the installed library version, it would be better to have code that checks the current zarr version and then load according to the installed version. Also wrap the loading code with a helpful error if it fails.

[felixS27]

Hi,
thank you for your answer. I just tried the fix with zarr version 2 and zarr version 3 and the fix works with both zarr versions.
The fix I propose is actually only to be more explicit in naming the input parameter of zarr.open() instead of relying on positional arguments. (As far as I understand in zarr 3 they are more strict about the input arguments and rely on named arguments)
So In my opinion there is no need to check the current zarr version.
But I am open to learn more.