fix test for specific error message

Author: d-v-b

tests/test_group.py

@@ -2220,7 +2220,7 @@ def test_build_metadata_v3(option: Literal["array", "group", "invalid"]) -> None
             metadata_dict = GroupMetadata(zarr_format=3).to_dict()
             metadata_dict.pop("node_type")
             # TODO: fix the error message
-            msg = r"Invalid value for 'node_type'. Expected 'array' or 'group'. Got nothing \(the key is missing\)."
+            msg = "Required key 'node_type' is missing from the provided metadata document."
             with pytest.raises(MetadataValidationError, match=msg):
                 _build_metadata_v3(metadata_dict)