Exclude revert & discard pages from overrides

Problem/Motivation

When using this module, the revert/discard changes forms can lose their formatting if another process like https://www.drupal.org/project/layout_builder_admin_theme → tries to bring them back into the admin theme. Since they're totally separate forms, we shouldn't mess with them.

Steps to reproduce

layout_builder_admin_theme isn't directly compatible with this, so reproduction would involve adding custom code like https://git.drupalcode.org/project/layout_builder_admin_theme/-/blob/8.x... into a custom module.

Proposed resolution

Ignore revert and discard changes routes.

Remaining tasks

User interface changes

API changes

Data model changes