Add "scroll to end of page" option to Lighthouse

**Feature request summary**

We get a lot of feedback where Lighthouse does not match CrUX for CLS ([example](https://groups.google.com/a/chromium.org/g/chrome-ux-report/c/KWU-UeoEe2I/m/S2k4n3KcAgAJ)). Often this is due to items "below the fold" without explicit dimensions. It would be good to be able to have a "Scroll to bottom of page after load" option in Lighthouse to pick those up - perhaps highlighted if lab CLS has large mismatch with field CLS?

**What is the motivation or use case for changing this?**

Help developers identify more CLS items using Lighthouse

**How is this beneficial to Lighthouse?**

This potentially allows more information to be gathered in Lighthouse for CLS, but also other audits. For example we can see the true size of the page once all lazy loaded components have been loaded.

It could also form the basis of more "conditional" audits, for example interaction audits using [User flows](https://web.dev/lighthouse-user-flows/) to help identify INP issues.