Page: tabIndex default value (mainTabIndex=-1) which prevents keyboard scroll

Describe the issue. What is the expected and unexpected behavior?
mainTabIndex=-1 as a default value prevents keyboard scroll. tlabindex should be removed. Having a tabindex on a container essentially breaks focus and keyboard scroll for all non-focusable containers below it. eg topology details side panel.

Any contributions to the main content should not have to deal with adding their own tabindex attribute to their scroll containers.

Above notes from the pr: https://github.com/openshift/console/pull/9140#issuecomment-854134911

workaround is to set the mainTabIndex to null.

Please provide the steps to reproduce. Feel free to link CodeSandbox or another tool.

https://github.com/openshift/console/pull/9140#issuecomment-8541349113

Is this a bug or enhancement? If this issue is a bug, is this issue blocking you or is there a work-around?
Bug
What is your product and what release version are you targeting?
OpenShift 4.9

从所引用的 PatternFly React pull request #9140 及其链接的 issue comment 入手，找到 mainTabIndex 的默认值。移除默认的 tabindex 行为，然后验证不可聚焦容器无需 mainTabIndex workaround 即可使用键盘滚动。