Test that `s` as a Dask Array is preserved
Test that `s` as a Dask Array is preserved

Ensure that if `s` is a Dask Array, it will still be a Dask Array after
type normalization is done on the input arguments of the Fourier
filters. This allows Fourier filters to construct a computation around
an unknown `s` in addition to an unknown input array.

dask-image/dask-ndfourier