List tables with fixed header on scroll

[Apiweb]

I think it would be interesting, the WordPress through their APIs, allowing fix the header of a table when the scroll action is happening.

A page that could make use of this functionality is the Posts list.

and

When the user has many posts, to scroll down the page, the table header is not more visible.
This could also be very useful for plugin authors. That have pages with listings.

[swissspidy]

I like the idea. Some movement here can't hurt.

[karmatosed]

I think I'd need to feel this in a patch. I'm a little concerned about multiple panels and what happens on certain pages. That said, if we can get a patch and run through the paces, things will be easier to evaluate. I would also suggest we turn this off for mobile and consider any a11y implications we may be causing.

[karmatosed]

For now removing ui-feedback until we have a patch, as talked about in this week's design triage meeting.

Trac Ticket: Core-31284

## Description
This pull request introduces a UI improvement in the admin area's table list view. Issue: When users have many posts and need to scroll down, the table header disappears from view. This update ensures that the table header remains visible, which can also benefit plugin authors who create pages with extensive lists.

## Testing

• Verify that the table header stays fixed at the top, below the WP admin bar, for both desktop and mobile devices. This functionality should also apply to custom WordPress list table views.