LayoutBuilderIsActiveCacheContext not providing correct context value.

Problem/Motivation

layout_builder_is_active cache context implemented in \Drupal\layout_builder\Cache\LayoutBuilderIsActiveCacheContext does not seem to be providing the correct cache context value - it is always 0. Issues seem to be:

• getContext() calls getDisplay(). getDisplay()checks whether the entity parameter from the route is an instance of OverridesSectionStorageInterface. AFAICT, OverridesSectionStorageInterface is not implemented by any entity classes; it's just the interface for the overrides section storage plugin. In which case, getDisplay() always returns NULL.
• Docblock for getDisplay() says the method should return \Drupal\layout_builder\Entity\LayoutEntityDisplayInterface, but even assuming there is an entity implementing OverridesSectionStorageInterface, getDefaultSectionStorage() returns \Drupal\layout_builder\DefaultsSectionStorageInterface, not \Drupal\layout_builder\Entity\LayoutEntityDisplayInterface
• Class docblock says that the cache context is to be used to "Determines whether Layout Builder is active for a given entity type or not.", but it seems the intent of the code is to determine whether a specific entity has layout builder overrides enabled.
• There isn't any test coverage for this cache context.

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet