Prometheus.spec.enforcedNamespaceLabel

When not empty, a label will be added to 1. All metrics scraped from `ServiceMonitor`, `PodMonitor`, `Probe` and `ScrapeConfig` objects. 2. All metrics generated from recording rules defined in `PrometheusRule` objects. 3. All alerts generated from alerting rules defined in `PrometheusRule` objects. 4. All vector selectors of PromQL expressions defined in `PrometheusRule` objects. The label will not added for objects referenced in `spec.excludedFromEnforcement`. The label's name is this field's value. The label's value is the namespace of the `ServiceMonitor`, `PodMonitor`, `Probe` or `PrometheusRule` object.