Description

I'm testing 6.7-RC-3, and noticed that when you still have blocks using v2 of the blockApi, that any metaboxes below the content editor are pushed very far away from the bottom of your content (so far that I'm concerned people won't even see them).

Step-by-step reproduction instructions

1. Have a block registered with v2 of the block API
2. Have a plugin that adds a metabox below the content
3. Notice how the gap between content and the metabox is huge (starting only with 6.7)

Screenshots, screen recording, code snippet

Environment info

WP 6.7-RC-3, no Gutenberg plugin.
Theme: Twentytwentyfive (and others)
Windows 10

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