Merge pull request optuna#5907 from boringbyte/fix/test_intermediate_plot.py

Simplify type annotations for `tests/visualization_tests/test_intermediate_plot.py`

Author: nabenabe0928

tests/visualization_tests/test_intermediate_plot.py

@@ -1,7 +1,9 @@
+from __future__ import annotations
+
+from collections.abc import Callable
+from collections.abc import Sequence
 from io import BytesIO
 from typing import Any
-from typing import Callable
-from typing import Sequence
 
 import pytest