Fix test_image_filter test error (#6624)

Fixes #6622 .

### Description

Add type check to avoid comparing a np.array with a string

### Types of changes
<!--- Put an `x` in all the boxes that apply, and remove the not
applicable items -->
- [x] Non-breaking change (fix or new feature that would not break
existing functionality).
- [x] Quick tests passed locally by running `./runtests.sh --quick
--unittests --disttests`.
- [x] In-line docstrings updated.

---------

Signed-off-by: Mingxin Zheng <mingxinz@nvidia.com>
Signed-off-by: Mingxin <18563433+mingxin-zheng@users.noreply.github.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: mingxin-zheng

monai/transforms/utility/array.py

@@ -1641,7 +1641,22 @@ def _check_filter_format(self, filter: str | NdarrayOrTensor | nn.Module, filter
                 "`class 'torch.nn.modules.module.Module'`, `class 'monai.transforms.Transform'`"
             )
 
-    def _check_kwargs_are_present(self, filter, **kwargs):
+    def _check_kwargs_are_present(self, filter: str | NdarrayOrTensor | nn.Module, **kwargs: Any) -> None:
+        """
+        Perform sanity checks on the kwargs if the filter contains the required keys.
+        If the filter is ``gauss``, kwargs should contain ``sigma``.
+        If the filter is ``savitzky_golay``, kwargs should contain ``order``.
+
+        Args:
+            filter: A string specifying the filter, a custom filter as ``torch.Tenor`` or ``np.ndarray`` or a ``nn.Module``.
+            kwargs: additional arguments defining the filter.
+
+        Raises:
+            KeyError if the filter doesn't contain the requirement key.
+        """
+
+        if not isinstance(filter, str):
+            return
         if filter == "gauss" and "sigma" not in kwargs.keys():
             raise KeyError("`filter='gauss', requires the additional keyword argument `sigma`")
         if filter == "savitzky_golay" and "order" not in kwargs.keys():