Make the block settings menu item dynamic

[afercia]

This PR tries to improve the interaction with the "Settings" menu item in the blocks "ellipsis" menu as detailed in #3340 (comment)

TODO: add a speak message when the sidebar block tab opens.

It's a first try to test if the new interaction makes sense, can be improved later.

Basically the item label and action are "dynamic" meaning they change based on the sidebar tab state:

Also, renames the label (and tooltip) for the block ellipsis menu: I've opted for "More options", inspired by a similar control in Gmail > compose:

Note: when a control uses aria-expanded, it's better to not change its label as, for example:
Open Settings Menu - collapsed
Close Settings Menu - expanded

would sound a bit weird. Note that the similar control in Gmail uses aria-expanded and doesn't change the label.

Also renames the sidebar ARIA region to Editor advanced settings.

Fixes #3340

[jasmussen]

I really reallly dig this 🏅

👍 👍 from me for all of this.

Code looks good to me too, though it couldn't hurt to get a quick 👍 from @youknowriad.