Navigation Block: block wrapper class name applied to both outer element and its child element

[talldan]

Description

If you inspect the markup of a navigation block with the overlay turned off (makes it easier to reproduce), the wp-block-navigation class name is applied twice, once to the outer <nav> and once to its child <ul>:

<nav class="wp-block-navigation is-layout-flex wp-block-navigation-is-layout-flex" aria-label="Navigation 2">
<ul class="wp-block-navigation__container  wp-block-navigation">

Blocks should only have the wrapper classname on the outermost element.

The bug seems to be caused by get_block_wrapper_attributes being used to compute the attributes of the <ul> element:

gutenberg/packages/block-library/src/navigation/index.php

Lines 177 to 182 in 4907090

	$container_attributes = get_block_wrapper_attributes(
	array(
	'class' => 'wp-block-navigation__container ' . $class,
	'style' => $style,
	)
	);

A concern is that changing this might cause some issues, it'd require a dev note as it may break some styles, but I think it needs to be fixed to ensure themes don't end up with unsual style rules like ul.wp-block-navigation.

Step-by-step reproduction instructions

1. Add a naviation block
2. Turn off the overlay
3. Preview the frontend
4. Inspect the markup

Screenshots, screen recording, code snippet

No response

Environment info

Reproduced on latest trunk core/gutenberg

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