Fix sparse typing

[Illviljan]

Fixes the following pyright error on main:

  C:\Users\J.W\Documents\GitHub\xarray\xarray\namedarray\core.py:846:39 - error: Argument of type "NDArray[Any]" cannot be assigned to parameter "data" of type "duckarray[_ShapeType_co@NamedArray, _DType_co@NamedArray] | Default" in function "_replace"
    Type "NDArray[Any]" cannot be assigned to type "duckarray[_ShapeType_co@NamedArray, _DType_co@NamedArray] | Default"
      "NDArray[Any]" is incompatible with protocol "_arrayfunction[_ShapeType_co@NamedArray, _DType_co@NamedArray]"
        Type "(dtype: None = ..., /) -> ndarray[Any, _dtype]" cannot be assigned to type "(dtype: _DType@__array__, /) -> ndarray[Any, _DType@__array__]"
          Parameter 1: type "_DType@__array__" cannot be assigned to type "None"
            Type cannot be assigned to type "None"
        Type "(dtype: None = ..., /) -> ndarray[Any, _dtype]" cannot be assigned to type "(dtype: _DType@__array__, /) -> ndarray[Any, _DType@__array__]"
          Parameter 1: type "_DType@__array__" cannot be assigned to type "None"
            Type cannot be assigned to type "None"
    ... (reportGeneralTypeIssues)