ResampleToMatch shouldn't always require `FILENAME_OR_OBJ`

[wyli]

Describe the bug

MONAI/monai/transforms/spatial/array.py

Line 353 in 86c7ecd

original_fname = img.meta[Key.FILENAME_OR_OBJ]

this metadata update was too restrictive:

File ~/Software/anaconda3/envs/monai/lib/python3.9/site-packages/monai/transforms/spatial/array.py:419, in ResampleToMatch.__call__(self, img, img_dst, src_meta, dst_meta, mode, padding_mode, align_corners, dtype)
    409 dst_affine = img_dst.affine if isinstance(img_dst, MetaTensor) else torch.eye(4)
    410 img = super().__call__(
    411     img=img,
    412     dst_affine=dst_affine,
   (...)
    417     dtype=dtype,
    418 )
--> 419 self.update_meta(img, dst_affine=dst_affine, img_dst=img_dst)
    420 return img

File ~/Software/anaconda3/envs/monai/lib/python3.9/site-packages/monai/transforms/spatial/array.py:349, in ResampleToMatch.update_meta(self, img, dst_affine, img_dst)
    347     super().update_meta(img, dst_affine)
    348 if isinstance(img_dst, MetaTensor) and isinstance(img, MetaTensor):
--> 349     original_fname = img.meta[Key.FILENAME_OR_OBJ]
    350     img.meta = deepcopy(img_dst.meta)
    351     img.meta[Key.FILENAME_OR_OBJ] = original_fname

KeyError: 'filename_or_obj'

maybe it can be skipped with:

- original_fname = img.meta[Key.FILENAME_OR_OBJ]
+ original_fname = img.meta.get(Key.FILENAME_OR_OBJ)