core: cleanup/sort imports according to ruff check --select I

my/core/tests/denylist.py

@@ -1,8 +1,8 @@
-from datetime import datetime
 import json
-from pathlib import Path
-from typing import NamedTuple, Iterator
 import warnings
+from datetime import datetime
+from pathlib import Path
+from typing import Iterator, NamedTuple
 
 from ..denylist import DenyList