[DATA Grid] Switch Header columns focus handling to native

[kertal]

When working on #3087 I've experienced that the current handling of header columns doesn't work well when there are multiple focusable elements in the header. Navigating with the tab key, I expected that I could navigate all focusable elements with tab key, but I could just navigate to the first button, the next tab switched to the "Rows per page element". Removing the header columns from focus management, would simplify the code a lot, make it less vulnerable to errors (it's currently broken in master), and I think tab navigation would work better. The downside is that you can no longer navigate from body to header with arrow keys (Personally I'd say use tabs for configuration, arrows for data).

That's the current behavior:

An here's the one switching to tabs

[myasonik]

I don't think this is something we can safely change. With such a complex component and with the absolute lack of testing that we do with real users, the best we can do is stick the best practices and the spec which this would go against (to the best of my knowledge and research).

While switching to native focus handling might make for simpler code, it will completely break screen reader expectations making the grid much harder to navigate and understand.

There's a separate issue (#3860) open for fixing the table header navigation.

[kertal]

I see, and we can't detect screenreaders, right? np. closing this