Details Block - enable expansion of more than one block at a time in the editor

[dansoschin]

While editing a details block, if you have multiple details blocks on your page, you can only have one expanded (to reveal the hidden content) at a time. However, there are many times when you might want multiple details blocks open at once so you can see all the content on your page easily and without shifting content north and south as you expand and collapse each block.

[dansoschin]

Reported in Github for Gutenberg -- ​https://github.com/WordPress/gutenberg/issues/54551

[sabernhardt]

Thanks for moving these reports!