Accessibility: add role=group to block wrapper element

[ellatrix]

Description

As suggested by @MarcoZehe. Apparently NVDA otherwise "silences" the tab stop.

https://www.w3.org/TR/wai-aria-1.1/#group

Authors SHOULD use a group to form logical collection of items in a widget such as children in a tree widget forming a collection of siblings in a hierarchy, or a collection of items having the same container in a directory.

How has this been tested?

Screenshots

Types of changes

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.
• I've updated all React Native files affected by any refactorings/renamings in this PR. .