Correct typing for _sparsearray (#8395)

* Update _typing.py

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update _typing.py

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

xarray/namedarray/_typing.py

@@ -3,7 +3,6 @@
 from collections.abc import Hashable, Iterable, Mapping, Sequence
 from types import ModuleType
 from typing import (
-    TYPE_CHECKING,
     Any,
     Callable,
     Protocol,
@@ -16,10 +15,6 @@
 
 import numpy as np
 
-if TYPE_CHECKING:
-    from numpy.typing import NDArray
-
-
 # https://stackoverflow.com/questions/74633074/how-to-type-hint-a-generic-numpy-array
 _T = TypeVar("_T")
 _T_co = TypeVar("_T_co", covariant=True)
@@ -234,7 +229,7 @@ class _sparsearray(
     Corresponds to np.ndarray.
     """
 
-    def todense(self) -> NDArray[_ScalarType_co]:
+    def todense(self) -> np.ndarray[Any, _DType_co]:
         ...