Describe the bug
Only the "most used" accordion is accessible (though with an invisible focus), while the other accordions are not. Besides that, after the 'last tab,' in this case when pressing tab on the 'system' item, the focus is completely lost. (see video)

To Reproduce
Steps to reproduce the behavior:

1- Go to https://demo.plone.org/edit
2- enter in edit mode by clicking on the edit button (top-left)
3- Press enter to create a new content
4- Click on the "add block" icon
5- Navigate using tab key

Expected behavior
After 'system,' the focus should move to the next accordion. Here, I see two possibilities:
1- The first accordion closes, the second one opens, and the focus goes to the first item of the second accordion.
2- The focus remains outside of the second accordion, on the accordion header, with the accordion closed. It opens only if the user wants. In this case, the next tab goes to the next accordion header.

Any way, the focus must remain inside the modal in a loop because the user don't know when the options actually finish.

Problem to be tackled alongside the previous item:

• And If the user do not wish to select any option and want to exit the 'blocks chooser'?
  The ESC key closes the modal, but it may not be intuitive. Perhaps adding an 'X' button to close it and properly return the focus inside the block would be a more user-friendly solution.

Screenshots
If applicable, add screenshots to help explain your problem.
https://github.com/plone/volto/assets/60133113/9ae96eb0-57ab-454b-8f92-a417709b1846