Step-by-step reproduction instructions

1. Ensure you're editing a template with enough content that a scrollbar displays
2. Select a block and open the block settings dropdown
3. Scroll the content

Expected: the block settings dropdown scrolls with the content (matching the toolbar's position)
Actual: the block settings dropdown remains in place while scrolling

Screenshots, screen recording, code snippet

Environment info

Latest trunk

Reproduced using Mac OS / Brave

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