Remove unused import of warnings from dataitems.py

Author: PierreRaybaut

guidata/dataset/dataitems.py

@@ -95,7 +95,6 @@
 import datetime
 import os
 import re
-import warnings
 from collections.abc import Callable
 from enum import Enum, EnumMeta
 from typing import TYPE_CHECKING, Any, Generic, Iterable, TypeVar