Fix get_chunked_array_type rejecting arrays of the same chunk manager

[IMGillusion]

What this PR does

get_chunked_array_type compared the exact type() of each array, so two
array classes handled by the same chunk manager (e.g. dask.Array and a
subclass of it, or any manager whose is_chunked_array is an
isinstance check against several classes) were reported as a mix of
chunked array types:

TypeError: Mixing chunked array types is not supported, but received
multiple types: {<class 'dask.array.core.Array'>, <class 'MyDaskArray'>}

The check now resolves which chunk manager recognises each array and
requires all arrays to be handled by the same manager. A genuine mix of
frameworks (e.g. a dask array together with a cubed array) still raises
TypeError.

What the PR achieves

Fixes #11539

To test this PR

import dask.array as da
import numpy as np
import xarray as xr

class MyDaskArray(da.Array):
    pass

plain = da.from_array(np.array([1, 2, 3]), chunks=(1,))
subclass = MyDaskArray(plain.dask, plain.name, plain.chunks, plain.dtype)

xr.Dataset({"a": ("x", plain), "b": ("x", subclass)}).load()  # now works

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