Save latest phishing-detect config list to disk on update

Currently if MetaMask is unable to reach the latest phishing-detect list, it falls back to its local copy of `eth-phishing-detect`, which can be old (since the core module is stable and rarely receives changes).

This means we fallback to some outdated phishing detection list, though. It would be better if the client would remember the latest "live" state it was aware of, and fell back to that first.

Related to issues like https://github.com/MetaMask/eth-phishing-detect/issues/4192

No files or tests are named. Start by tracing how the extension updates and falls back to the eth-phishing-detect list, then identify where the live list can be persisted; done means the latest known live state is saved and preferred when the list cannot be reached.

Written by the indexing model from the issue text.