Layout Settings Styles are broken since D10

Problem/Motivation

Now that the Cores offcanvas CSS reset reached desctruction level 10.000, we need to adress this - again:

https://www.drupal.org/node/3305664 →
https://www.drupal.org/project/drupal/issues/2853222 →
https://www.drupal.org/project/drupal/issues/2826722 →
https://www.drupal.org/project/drupal/issues/2853208 →
https://herchel.com/articles/new-drupal-core-refactored-canvas-dialog-css

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes