Zoom Out: "Desktop (50%)" view hides breadcrumbs and doesn't work in non-iframe editor

[t-hamano]

Description

There seem to be two issues with the "Desktop (50%)" view introduced in #63870:

• The block breadcrumbs is hidden This appears to be the expected behavior, see this comment.
• Doesn't work in non-iframe editor

Step-by-step reproduction instructions

• Open the post editor.
• Click the View button and Select "Desktop (50%)"
• The block breadcrumbs should be hidden.
• Enalbe Custom fields.
• Click the View button and Select "Desktop (50%)"
• Nothing should happen.

Screenshots, screen recording, code snippet

5a36320a6b5c0b9b094cc575ea7a7d5e.mp4

Environment info

No response

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

[stokesman]

• Doesn't work in non-iframe editor

I made #62943 regarding that. I imagined that the iframe would have to be forced if when Zoom Out is engaged which if possible would seemingly also fix this.