Description

Variation of core/button block are not available in the core/buttons inserter.

I expect to see the variations when adding button.

Step-by-step reproduction instructions

1. Add the code snippet provided below to WordPress
2. Create or edit a post
3. Add a "Buttons" block

Only the basic block "button" is available, the variations can't be used.

4. Open the browser devtools
5. In the console, run wp.blocks.getBlockVariations('core/button');

The two registered variations are correctly listed as a result.

Screenshots, screen recording, code snippet

Small code snippet to demonstrate the issue.

<?php
add_action( 'enqueue_block_editor_assets', function () {
	wp_enqueue_script( 'wp-blocks', );
	wp_add_inline_script(
		'wp-blocks',
		"
        wp.blocks.registerBlockVariation('core/button', {
            name: 'custom-button',
            label: 'My custom button',
            attributes: {className: 'my-custom-button'},
        });
        
        wp.blocks.registerBlockVariation('core/button', {
            name: 'custom-button-default',
            label: 'My custom button (Default variation)',
            attributes: {className: 'my-custom-button-default'},
            isDefault: true
        });
        ",
        'after'
	);
} );

Environment info

• WordPress 6.3, Gutenberg 16.4.0, TwentyTwentyThree
• Firefox / Chrome
• Desktop mac 13

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes