Block Styles: Allow registration across multiple block types at once

[aaronrobertshaw]

This ticket tracks the backporting of PHP files for the following Gutenberg changes:

​https://github.com/WordPress/gutenberg/pull/61029

The Gutenberg PR linked above was forced to add a new global function because the core WP_Block_Styles_Registry class was marked as final. The backport for this will involve updating the WP_Block_Styles_Registry class directly with matching functionality.

Included is the addition of style_data within the supported style properties. The style_data property is a theme.json shaped array which will be used by the new section styling feature to generate a dynamic stylesheet for the block style.

Adds to core the functionality from:

• ​https://github.com/WordPress/gutenberg/pull/61029

The Gutenberg PR linked above was forced to add a new global function because the core WP_Block_Styles_Registry class was marked as final. This backport involves updating the WP_Block_Styles_Registry class directly with matching functionality.

Included is the addition of style_data within the supported style properties. The style_data property is a theme.json shaped array that will be used by the new ​section styling feature to generate a dynamic stylesheet for the block style.

Trac ticket: https://core.trac.wordpress.org/ticket/61274

[isabel_brison]

In 58246:

Editor: allow registering block styles for multiple block types.

Updates the WP_Block_Styles_Registry class to allow registering an array of blocks.

Props aaronrobertshaw, talldanwp, isabel_brison.
Fixes #61274.

Committed in r58246.

[swissspidy]

In 58247:

Editor: Improve types in docblock after [58246].

Makes it clearer that an array of strings is expected.

See #61274.