Features: Investigate what happens to features on downgrade

### Details

We've added a new features framework: D63248-code and aligned Calypso with the available settings/features in some instances. For example, SEO and Analytics settings: https://github.com/Automattic/wp-calypso/pull/53196. Also security settings: https://github.com/Automattic/wp-calypso/pull/53484

We need a downgrade flow for these features. What happens when you no longer have access? Do they reset to the defaults?

### Checklist

- [ ] Check what happens to these features on downgrade now.
- [ ] Make any fixes necessary.

### Related

https://github.com/Automattic/wp-calypso/issues/54735

Start by reviewing the feature framework referenced as D63248-code and the SEO/Analytics and security changes in PRs #53196 and #53484, then compare their behavior with the downgrade flow. Check the related issue #54735 and document what happens to each feature after access is removed; done means the behavior is verified and any necessary fixes are covered.

Written by the indexing model from the issue text.