Allow to set user id for Sentry events

Sending user id would allow Sentry to show me how many distinct users (Kubernetes Agents in my case) are returning an error. See https://docs.sentry.io/product/sentry-basics/guides/integrate-backend/capturing-errors/#enriching-your-event-data and https://docs.sentry.io/platforms/go/enriching-events/identify-user/