system::monitoring::monitoring_tests covers the defaults, metric
sampling, the Prometheus gauges, trace history over SMTP and LMTP
(probe sessions skipped, no raw I/O), trace destroy, indexTelemetry off,
live metrics and live tracing with their tokens and stream limit,
alerts by event and by email, and tenant admins refused. Also removes a
leftover enterprise-only attribute on the Prometheus counters loop,
which would have dropped counters from an enterprise-feature build.