Description

With Gutenberg trunk, the stylesheet added via add_editor_style() is no longer working.

Step-by-step reproduction instructions

For example, TT5 has a editor-style.css, and to make it easier to see the difference, let's make h1 have a red background :)

h1 {
	background-color: red;
}

Save the CSS and open the editor.

No h1 has the red background in the editor.

If you disable the plugin, we can see a h1 with a red background.

Screenshots, screen recording, code snippet

No response

Environment info

WP 6.9
Gutenberg trunk

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

Please confirm which theme type you used for testing.

• Block
• Classic
• Hybrid (e.g. classic with theme.json)
• Not sure