Improvement to error message for writing attributes to a Zarr group in MATLAB

[jm9176]

Writing attribute to a group throws "Not a valid Zarr array or group" error, even though the group is valid and exists. So, maybe the error message can be improved?

>> zarrwriteatt('myFile/','attr1',10)
Error using zarrinfo (line 36)
Not a valid Zarr array or group

Error in zarrwriteatt (line 21)
info = zarrinfo(filepath);
       ^^^^^^^^^^^^^^^^^^

[abhibaruah]

@jm9176 Can you check if you still see this error?
I tried the repro steps on a valid group (a folder that contains a valid .zgroup file) and zarrwriteatt does behave as expected.
It creates a .zattrs file as expected.

If I call zarrwriteatt on a folder that does not contain .zgroup file, an error is thrown which is expected behavior.