Describe the bug

type annotation for Index/MultiIndex.names is incorrect

To Reproduce

1. Provide a minimal runnable pandas example that is not properly checked by the stubs.

In [1]: import pandas as pd

In [2]: df = pd.DataFrame({"a": ["a", "b", "c"], "i": [10, 11, 12]}, index=pd.Index([5, 10, 15], name="idx"))

In [4]: df.index.names
Out[4]: FrozenList(['idx'])

In [5]: df.index.names = (None,)

In [6]: df.index.names
Out[6]: FrozenList([None])

1. Indicate which type checker you are using (mypy or pyright).

mypy

1. Show the error message received from that type checker while checking your example.

bigframes/core/blocks.py:436: error: Incompatible types in assignment (expression has type "tuple[None]", variable has type "list[str]") [assignment]

Please complete the following information:

• OS: [e.g. Windows, Linux, MacOS] Linux
• OS Version [e.g. 22]

Distributor ID: Debian
Description: Debian GNU/Linux rodete
Release: n/a
Codename: rodete

• python version Python 3.10.9
• version of type checker mypy==1.5.1
• version of installed pandas-stubs pandas-stubs==2.0.3.230814

Additional context
Add any other context about the problem here.