Block Supports: Add width support to dimensions block supports

[aaronrobertshaw]

This ticket tracks the backport of PHP files for the following Gutenberg updates:

​https://github.com/WordPress/gutenberg/pull/71905

These updates include the PHP changes to add width block supports.

New dimensions block supports are being added to support new blocks such as the proposed Icon block. See ​https://github.com/WordPress/gutenberg/pull/71227 for further context.

Trac ticket: https://core.trac.wordpress.org/ticket/64200

This PR brings the changes from the following Gutenberg PRs to core:

​https://github.com/WordPress/gutenberg/pull/71905

### Description

Adds a new dimensions.width block support to facilitate the creation of new blocks such as the Icon block.

See: ​https://github.com/WordPress/gutenberg/pull/71227

### Testing

1. Adopt width block support for a dynamic block e.g. Cover via its block.json file
2. Add a width value for the chosen test block in your theme.json file
3. Create a post with the test block type
4. Confirm the global style is applied to your test block