Move phish warning page to metamask.io domain

Currently when you attempt to navigate to a blocked site, the redscreen page is served from `https://metamask.github.io/phishing-warning/v3.0.0/.........`

The warning page is our authority page to let users know of a scam they are about to visit. If we continue to serve it on non-metamask.io domain, we are training users to trust non-metamask domains for this security control.

Moving to metamask domain will isolate it from the rest of the metamask experiments that are served under `metamask.github.io/`

## Ref Links

- https://github.com/search?q=org%3AMetaMask+metamask.github.io%2Fphishing-warning&type=code

- extension https://github.com/MetaMask/metamask-extension/blob/develop/development/build/scripts.js#L191

- also some ledger thing also served from here: https://github.com/MetaMask/metamask-extension/blob/develop/offscreen/ledger-iframe.html

- mobile doesn't seem to be serving the same page lol. It's serving a page that apparently ships with the app?

- https://github.com/MetaMask/metamask-mobile/blob/main/app/components/UI/PhishingModal/index.js


Start by tracing the deployment for metamask.github.io/phishing-warning and the extension references in development/build/scripts.js and offscreen/ledger-iframe.html. Review the linked mobile implementation in app/components/UI/PhishingModal/index.js, then identify all consumers that must point to the metamask.io-hosted warning page; done means the warning is served from the MetaMask domain without breaking those consumers.

Written by the indexing model from the issue text.