id,node_id,number,title,user,state,locked,assignee,milestone,comments,created_at,updated_at,closed_at,author_association,active_lock_reason,draft,pull_request,body,reactions,performed_via_github_app,state_reason,repo,type
2024303763,I_kwDOAMm_X854qGyT,8516,Appending to a ZARR dataset removes dimension separator attribute,31890,open,0,,,1,2023-12-04T16:52:27Z,2023-12-04T17:42:37Z,,NONE,,,,"### What happened?

When creating a ZARR store with `dimension_separator=""/""`, the `to_zarr_store` method removes `dimension_separator` attribute in the `.zarray` file.

### What did you expect to happen?

It should retain the original storage attributes.

### Minimal Complete Verifiable Example

```Python
import json

import xarray as xr
from zarr.storage import MemoryStore


store = MemoryStore(dimension_separator=""/"")

ds = xr.Dataset(
    {""data"": xr.DataArray([0.0], dims=(""x"",))},
    coords={
        ""x"": xr.DataArray([0.0], dims=(""x"",)),
    },
)
ds.to_zarr(store, mode=""w"", consolidated=False)
assert json.loads(store[""data/.zarray""].decode()).get(""dimension_separator"") == ""/""

ds = xr.Dataset(
    {""data"": xr.DataArray([1.0], dims=(""x"",))},
    coords={
        ""x"": xr.DataArray([1.0], dims=(""x"",)),
    },
)
ds.to_zarr(
    store,
    append_dim=""x"",
    consolidated=False
)
assert json.loads(store[""data/.zarray""].decode()).get(""dimension_separator"") == ""/""
```


### MVCE confirmation

- [X] Minimal example — the example is as focused as reasonably possible to demonstrate the underlying issue in xarray.
- [X] Complete example — the example is self-contained, including all data and the text of any traceback.
- [X] Verifiable example — the example copy & pastes into an IPython prompt or [Binder notebook](https://mybinder.org/v2/gh/pydata/xarray/main?urlpath=lab/tree/doc/examples/blank_template.ipynb), returning the result.
- [X] New issue — a search of GitHub Issues suggests this is not a duplicate.
- [X] Recent environment — the issue occurs with the latest version of xarray and its dependencies.

### Relevant log output

```Python
AssertionError                            Traceback (most recent call last)
File ~/xarray_repro/run.py:29
     18 ds = xr.Dataset(
     19     {""data"": xr.DataArray([1.0], dims=(""x"",))},
     20     coords={
     21         ""x"": xr.DataArray([1.0], dims=(""x"",)),
     22     },
     23 )
     24 ds.to_zarr(
     25     store,
     26     append_dim=""x"",
     27     consolidated=False
     28 )
---> 29 assert json.loads(store[""data/.zarray""].decode()).get(""dimension_separator"") == ""/""

AssertionError:
```


### Anything else we need to know?

_No response_

### Environment

<details>
INSTALLED VERSIONS
------------------
commit: None
python: 3.11.5 (main, Aug 24 2023, 15:18:16) [Clang 14.0.3 (clang-1403.0.22.14.1)]
python-bits: 64
OS: Darwin
OS-release: 22.5.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8
LOCALE: ('en_US', 'UTF-8')
libhdf5: None
libnetcdf: None

xarray: 2023.11.0
pandas: 2.1.3
numpy: 1.26.2
scipy: None
netCDF4: None
pydap: None
h5netcdf: None
h5py: None
Nio: None
zarr: 2.16.1
cftime: None
nc_time_axis: None
iris: None
bottleneck: None
dask: 2023.11.0
distributed: None
matplotlib: None
cartopy: None
seaborn: None
numbagg: None
fsspec: 2023.12.0
cupy: None
pint: None
sparse: None
flox: None
numpy_groupies: None
setuptools: 68.1.2
pip: 23.2.1
conda: None
pytest: None
mypy: None
IPython: 8.18.1
sphinx: None
</details>
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