typing: QTabBar.setTabButton() should accept None

According to documentation : https://doc.qt.io/qt-6/qtabbar.html#setTabButton

QTabBar.setTabButton() should accept None as the widget argument.
 
Example code :
 
from typing import Optional

from PySide6.QtWidgets import QTabBar

tabBar = QTabBar()
tabBar.setTabButton(0, QTabBar.ButtonPosition.LeftSide, None)

The above code should pass type verification without errors.