Add backward compatibility support for lightBlockWrapper in getSaveElement

[talldan]

Description

Fixes #26672

#25642 added support for the apiVersion: 2 block setting which replaces the lightBlockWrapper supports setting.

In some places in that PR, backwards compatibility for lightBlockWrapper was left in place:

• gutenberg/packages/block-editor/src/components/block-edit/edit.js

  Lines 54 to 57 in 0ca9736

  	if (
  	blockType.apiVersion > 1 ||
  	hasBlockSupport( blockType, 'lightBlockWrapper', false )
  	) {

• gutenberg/packages/block-editor/src/components/block-list/block.js

  Lines 137 to 139 in 1f0d0f5

  	const lightBlockWrapper =
  	blockType.apiVersion > 1 ||
  	hasBlockSupport( blockType, 'lightBlockWrapper', false );

But getSaveElement doesn't seem to have that, which causes the duplicate classnames described in #26672:

gutenberg/packages/blocks/src/api/serializer.js

Lines 119 to 123 in 1f0d0f5

	if (
	isObject( element ) &&
	hasFilter( 'blocks.getSaveContent.extraProps' ) &&
	! blockType.apiVersion
	) {

How has this been tested?

1. Load the post editor and register the following block by copying the code and running it in your browser console:

wp.blocks.registerBlockType( `example/example-new`, {
    title: wp.i18n.__( 'Example Block (New)', 'example' ),
    description: wp.i18n.__( 'Example Block', 'example' ),
    icon: 'smiley',
    category: 'common',
    example: {},
    supports: {
        html: false,
        lightBlockWrapper: true,
        align: true,
        anchor: true,
        color: {
            link: true
        },
    },
    attributes: {},
    transforms: {},
    variations: [],
    edit: () => {
        return wp.element.createElement( 'div', wp.blockEditor.useBlockProps(), 'Hello World' );
    },
    save: () => {
        return wp.element.createElement( 'div', wp.blockEditor.useBlockProps.save(), 'Hello World' );
    }
} );

2. Add the new block and set some custom colors
3. Preview the post and inspect the element created by the block
4. Confirm it has no duplicate classnames.

Types of changes

Bug fix (non-breaking change which fixes an issue)

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.

[github-actions]

Size Change: +19 B (0%)

Total Size: 1.2 MB

Filename	Size	Change
build/blocks/index.js	48.1 kB	+19 B (0%)

ℹ️ View Unchanged

Filename	Size	Change
build/a11y/index.js	1.14 kB	0 B
build/annotations/index.js	3.8 kB	0 B
build/api-fetch/index.js	3.42 kB	0 B
build/autop/index.js	2.83 kB	0 B
build/blob/index.js	665 B	0 B
build/block-directory/index.js	8.72 kB	0 B
build/block-directory/style-rtl.css	943 B	0 B
build/block-directory/style.css	942 B	0 B
build/block-editor/index.js	133 kB	0 B
build/block-editor/style-rtl.css	11.3 kB	0 B
build/block-editor/style.css	11.3 kB	0 B
build/block-library/editor-rtl.css	8.96 kB	0 B
build/block-library/editor.css	8.96 kB	0 B
build/block-library/index.js	148 kB	0 B
build/block-library/style-rtl.css	8.23 kB	0 B
build/block-library/style.css	8.23 kB	0 B
build/block-library/theme-rtl.css	792 B	0 B
build/block-library/theme.css	793 B	0 B
build/block-serialization-default-parser/index.js	1.87 kB	0 B
build/block-serialization-spec-parser/index.js	3.06 kB	0 B
build/components/index.js	172 kB	0 B
build/components/style-rtl.css	15.3 kB	0 B
build/components/style.css	15.3 kB	0 B
build/compose/index.js	9.93 kB	0 B
build/core-data/index.js	14.8 kB	0 B
build/data-controls/index.js	827 B	0 B
build/data/index.js	9.71 kB	0 B
build/date/index.js	11.2 kB	0 B
build/deprecated/index.js	769 B	0 B
build/dom-ready/index.js	571 B	0 B
build/dom/index.js	4.92 kB	0 B
build/edit-navigation/index.js	11.2 kB	0 B
build/edit-navigation/style-rtl.css	881 B	0 B
build/edit-navigation/style.css	885 B	0 B
build/edit-post/index.js	306 kB	0 B
build/edit-post/style-rtl.css	6.45 kB	0 B
build/edit-post/style.css	6.44 kB	0 B
build/edit-site/index.js	23.5 kB	0 B
build/edit-site/style-rtl.css	3.86 kB	0 B
build/edit-site/style.css	3.86 kB	0 B
build/edit-widgets/index.js	26.4 kB	0 B
build/edit-widgets/style-rtl.css	3.13 kB	0 B
build/edit-widgets/style.css	3.13 kB	0 B
build/editor/editor-styles-rtl.css	476 B	0 B
build/editor/editor-styles.css	478 B	0 B
build/editor/index.js	43.3 kB	0 B
build/editor/style-rtl.css	3.85 kB	0 B
build/editor/style.css	3.85 kB	0 B
build/element/index.js	4.62 kB	0 B
build/escape-html/index.js	735 B	0 B
build/format-library/index.js	6.86 kB	0 B
build/format-library/style-rtl.css	547 B	0 B
build/format-library/style.css	548 B	0 B
build/hooks/index.js	2.16 kB	0 B
build/html-entities/index.js	623 B	0 B
build/i18n/index.js	3.57 kB	0 B
build/is-shallow-equal/index.js	698 B	0 B
build/keyboard-shortcuts/index.js	2.85 kB	0 B
build/keycodes/index.js	1.94 kB	0 B
build/list-reusable-blocks/index.js	3.1 kB	0 B
build/list-reusable-blocks/style-rtl.css	476 B	0 B
build/list-reusable-blocks/style.css	476 B	0 B
build/media-utils/index.js	5.31 kB	0 B
build/notices/index.js	1.82 kB	0 B
build/nux/index.js	3.42 kB	0 B
build/nux/style-rtl.css	671 B	0 B
build/nux/style.css	668 B	0 B
build/plugins/index.js	2.56 kB	0 B
build/primitives/index.js	1.43 kB	0 B
build/priority-queue/index.js	790 B	0 B
build/redux-routine/index.js	2.84 kB	0 B
build/reusable-blocks/index.js	3.07 kB	0 B
build/rich-text/index.js	13.4 kB	0 B
build/server-side-render/index.js	2.77 kB	0 B
build/shortcode/index.js	1.69 kB	0 B
build/token-list/index.js	1.27 kB	0 B
build/url/index.js	4.05 kB	0 B
build/viewport/index.js	1.86 kB	0 B
build/warning/index.js	1.14 kB	0 B
build/wordcount/index.js	1.22 kB	0 B

_{compressed-size-action}

[tellthemachines]

This is working well!

[youknowriad]

lightBlockWrapper was never a stable API (you were forced to use __experimentalBlock in addition to it) so I'm really not sure this code is needed.

[youknowriad]

I guess it's ok for consistency but I wouldn't mind removing all of these fallbacks.