OBSDOCS-1608: Update the span RED metrics namespace

Signed-off-by: Ruben Vargas <[email protected]>

Author: rubenvp8510

modules/distr-tracing-tempo-config-spanmetrics.adoc

@@ -96,11 +96,13 @@ spec:
         monitorTab:
           enabled: true # <1>
           prometheusEndpoint: https://thanos-querier.openshift-monitoring.svc.cluster.local:9091 # <2>
+          redMetricsNamespace: "" <3>
         ingress:
           type: route
 ----
 <1> Enables the monitoring tab in the Jaeger console.
 <2> The service name for Thanos Querier from user-workload monitoring.
+<3> Optional: The metrics namespace on which the Jaeger query retrieves the Prometheus metrics. Include this line only if you are using an OpenTelemetry Collector version earlier than 0.109.0. If you are using an OpenTelemetry Collector version 0.109.0 or later, omit this line.
 
 [id="distr-tracing-tempo-config-spanmetrics_span-red-metrics-and-alerting-rules_{context}"]
 == Span RED metrics and alerting rules