Initialising Zarr3 from schema broken in 1.0.79

Code like the below used to work in 1.0.78, but it broke in 1.0.79. ```python dataset = await ts.open({ 'driver': 'zarr3', 'kvstore': kvstore, }) dataset2 = await ts.open({ 'driver': 'zarr3', 'kvstore': kvstore2, 'create': True, 'delete_existing': True, 'schema': dataset.schema, # FIXME: Broken in 1.0.79 }) ``` ```text File "...", line 76, in main new_dataset = await ts.open({ ~~~~~~~^^ 'driver': 'zarr3', ^^^^^^^^^^^^^^^^^^ ...<3 lines>... 'schema': dataset.schema, # FIXME: Broken in 1.0.79 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ }) ^^ TypeError: object of type 'tensorstore.Schema' has no len() ```