feat(perf-vitals): Add INP to the backend

[k-fish]

This adds INP as a web vital queryable to the backend, as well as adding it in the vitals endpoints, and adding it to the metrics layer since it should also be fetched as a metric as well.

Note: This is a draft for now since we don't necessarily want to turn this on until the js sdk is setup to send it. It will be a bit before this graduates into a real PR.