Error converting zarr v3 to zarr v2: zarr 2 does not support "Serializer"

What happened?

I'm trying to convert a Zarr dataset in the Zarr format/version 3 to 2. Xarray can successfully read zarr v2 or v3. I can make an xarray dataset in memory and write to disc in either zarr v2 or v3. I seem to find this problem only when reading an existing zarr v3 and and attempting to write to a zarr v2. However i can successfully convert the opposite direction by reading an existing zarr v2 and writing to zarr v3. Given that all the other read/write scenarios that i've tried work fine, i'm guessing there's some internal config set when reading a dataset from zarr v3 which maybe doesn't exist or has an incompatible default for in zarr v2.

What did you expect to happen?

I expected this to be possible

xr.open_zarr('v3path.zarr', zarr_format=3).to_zarr('v2path.zarr', zarr_format=2)

Minimal Complete Verifiable Example

import xarray as xr
import numpy as np

# generate a random array and write it to zarr v3
arr = np.random.rand(100, 100)
(
    xr
    .DataArray(arr, dims=['x', 'y'], name='data')
    .to_zarr(
        './test-v3.zarr',
        zarr_format=3
    )
)

# now try to convert it to a zarr 2
(
    xr
    .open_zarr('./test-v3.zarr')
    .to_zarr('test-v2.zarr', zarr_format=2)
)

MVCE confirmation

• Minimal example — the example is as focused as reasonably possible to demonstrate the underlying issue in xarray.
• Complete example — the example is self-contained, including all data and the text of any traceback.
• Verifiable example — the example copy & pastes into an IPython prompt or Binder notebook, returning the result.
• New issue — a search of GitHub Issues suggests this is not a duplicate.
• Recent environment — the issue occurs with the latest version of xarray and its dependencies.

Relevant log output

ValueError: Zarr format 2 arrays do not support `serializer`.

Anything else we need to know?

No response

Environment

This is on a google colab machine but i've also replicated this on so Mac and Windows installations

Start by reproducing the failure with the provided xarray.DataArray example and trace the interaction between xr.open_zarr and Dataset.to_zarr when changing from format 3 to format 2. Done means the conversion completes without the serializer error and the resulting Zarr v2 dataset can be opened successfully.