Bug - Notification Drawer should allow focus trap

Describe the problem
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When using a keyboard to navigate the page in https://www.patternfly.org/components/notification-drawer/react-demos/basic/, keyboard focus is given to the first button or link in the drawer, which is correct.

However, when a user goes and closes the notification drawer, keyboard focus does not return to the notification button, and seems to return to the browser chrome, which is disorienting.

Moreover, after tabbing to the last item in the notification drawer, the next tab press should loop back to the first item in the notification drawer; however, this is not done.

Expected behavior
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In the demo, keyboard focus should be returned to the notification badge after the notification drawer is closed, and the keyboard focus should be trapped entirely within the notification drawer when it is open.

Screenshots
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Any other information?

See this blog post:

https://codepen.io/unleashalicia/pen/YzXrJBN
https://knowbility.org/blog/2020/accessible-slide-menus

Jira Issue: PF-1354

从所链接的 PatternFly 页面上的 React notification-drawer 基础演示开始，并查看所链接的 focus-management 示例。验证 drawer 当前的键盘行为，然后确保关闭时 focus 返回 notification badge，并在打开的 drawer 内循环；在演示中验证这两种行为。