在窗口中嵌入QWebEngineView之后，窗口边框消失，阴影消失。

[riverbird]

Describe the bug A clear and concise description of what the bug is. 在窗口中嵌入qwebenginer之后，窗口边框消失，阴影消失。

Environment 环境信息

• OS: [e.g. Windows11]
• DPI scaling: [e.g. 100%]
• Python: [e.g. 3.11.7 64-bit]
• PySide6: [e.g. 6.6.1]

To Reproduce 复现问题的步骤，推荐使用 gif 进行演示。 Steps to reproduce the behavior(you can use GIF to demonstrate :):

1. 将QWebEngineView组件添加至QWidget当中的Layout当中；
2. 窗口边框消失，阴影消失。

Code 最小复现代码

# Minimum code to reproduce the error
self.tb_view = QWebEngineView()
self.tb_view.setObjectName('dot_note_preview')
self.tb_view.setContextMenuPolicy(Qt.ContextMenuPolicy.NoContextMenu)
self.tb_view.installEventFilter(self)

Expected behavior A clear and concise description of what you expected to happen.

Screenshots If applicable, add screenshots to help explain your problem.

[zhiyiYo]

有个历史 issue，你去找找