Remove unnecessary local storage (redux) for anonymous users

[tedw87]

• EU GDPR and Privacy related.

[ericof]

@tedw87 Please adda a Changelog entry

[avoinea]

@tedw87 Can you please check the CI errors?

[avoinea]

@tedw87 Login doesn't seem to work anymore with this branch.

[tedw87]

The idea of cleaning up localStorage for anonymous users makes sense, but there’s a critical edge case:
If a user signs in mid-session, the middleware can remove the needed persisted state right before the auth flow finishes, breaking the login.
Also, the initial state appears even for anonymous users because Volto core creates the store and saves persistantReducers to localStorage at initialization, before any auth checks run.
Given these issues, we can’t merge this as-is. I’ll close the PR for now