Experimenter ingestion: extend existing monitoring data with funnel rollup

[data-sync-user]

Extend the existing monitoring data computation + storage flow on NimbusExperiment to also include the funnel rollup from the ETL, alongside the enrollment counts already stored.

• Today, Experimenter already computes monitoring/enrollment data per recipe and passes it through to a stored field on NimbusExperiment — the same flow that powers the existing unenrollment/SRM alerts and badges.
• Extend that mechanism to also carry the funnel rollup. Same recipe-keyed routing, same field, same cadence.
• No new task, no new model — just a larger payload through the same pipe.

Acceptance

• Funnel rollup is fetched from the new BQ table and stored on each NimbusExperiment alongside its monitoring data.
• Daily cadence aligned with the ETL.

Depends on

• ETL (ticket 1)

┆Issue is synchronized with this Jira Task