This logic is used by the PostPublishPanel, which lives in editor.
We don't want editor to depend on anything from edit-post.

An alternative approach could be to keep the logic in edit-post
and use the the PrePublish and PostPublish extensions.
In my view, those are meant for allowing plugins to inject their
own panels into the PublishPanel. Dismissing the panel is a core
action and using the extensions to circumvent the editor/edit-post
separation would be a convoluted way to add support for dismissing the panel.

These data has been moved to edit-post store as per
#4661

In theory, isPublishSidebarEnabled shouldn't be ever undefined
in the preferences object, so this shouldn't be necessary.

In practice, we use a localStorage mechanism to persist
parts of the state in between sessions (like whether the user
has already seen the tips or not). For the core/editor store
we persist the preferences key, which contains an object.
This is the problem: the localStorage mechanism doesn't check
whether the cached preferences object and the state preferences object
have the same shape, it just overwrites the current state,
so new added keys are deleted.

While this bug is not fixed and deployed,
we want this preventive measure in place.