ci: add testing with Python 3.12 (#22813)

We need to use a different version of numpy for py3.8 and py3.12 in
pyproject.
And so do projects that use that Python version range and import
langchain.

    - **Twitter handle:** _cbornet

libs/community/tests/unit_tests/agents/test_tools.py

@@ -42,7 +42,7 @@ def test_single_input_agent_raises_error_on_structured_tool(
     with pytest.raises(
         ValueError,
         match=f"{agent_cls.__name__} does not support"  # type: ignore
-        f" multi-input tool {the_tool.name}.",
+        f" multi-input tool the_tool.",
     ):
         agent_cls.from_llm_and_tools(MagicMock(), [the_tool])  # type: ignore