Zoom out does not fully engage when editor is not iframed

[stokesman]

Description

In the Post editor when the preference to show custom fields is on and the inserter is open and inserting a pattern the zoom out mode doesn’t fully engage.

This also may happen in other conditions the editor is not iframed, for instance with a non-block theme and some blocks less than v3 but I haven’t tested that.

Step-by-step reproduction instructions

1. Open the Post Editor
2. Open the Preferences dialog
3. Enable Custom Fields
4. Open the Inserter and change to the Patterns tab and select a pattern category
5. Observe that the editor canvas does not zoom out but the zoom out inserters between blocks are present

Screenshots, screen recording, code snippet

Environment info

• WP 6.5 with Gutenberg plugin at trunk
• Chrome
• macOS

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