Block toolbar DOM order and visual order mismatch in the responsive view

[afercia]

Splitting this out from #9739

In the responsive view, the block toolbar changes position and it's placed after the block together with the block "movers" and the Add block button:

However, to my understanding there's some DOM repositioning but it's mainly a visual repositioning. The DOM order is mostly the same as in the desktop view. This way, visual order and DOM order mismatch and don't make any sense.

Worth reminding many screen reader users use a keyboard when using their mobile devices so keyboard operability is relevant also in the mobile view.

It's also a WCAG failure but, regardless, it makes operating with a keyboard nearly impossible and should be fixed. If a reordering is desired, it should change also the DOM order to match the visual order.