dogstatsd_non_local_traffic is true by default (#33018)

* `dogstatsd_non_local_traffic` is true by default

`dogstatsd_non_local_traffic` is set to true by default. Just adding a note to inform users, since the current documentation requests this to be configured, which is not necessary.
ZD: 2363535

* Update content/en/tracing/metrics/runtime_metrics/_index.md

---------

Co-authored-by: Esther Kim <esther.kim@datadoghq.com>

Author: kteixeiradd

content/en/tracing/metrics/runtime_metrics/_index.md

@@ -125,7 +125,7 @@ Enable [DogStatsD for the Agent][2]. By default, the Datadog Agent is configured
 
 When running the Agent in containerized environments, additional configuration is required:
 
-1. Set `dogstatsd_non_local_traffic: true` in your main [`datadog.yaml` configuration file][8], or set the [environment variable][3] `DD_DOGSTATSD_NON_LOCAL_TRAFFIC=true`.
+1. Set `dogstatsd_non_local_traffic: true` in your main [`datadog.yaml` configuration file][8], or set the [environment variable][3] `DD_DOGSTATSD_NON_LOCAL_TRAFFIC=true`. **Note**: DogStatsD non‑local traffic is enabled by default, so you only need to set this if you've overridden it.
 2. Follow these container-specific setup instructions:
 
 {{< partial name="apm/apm-runtime-metrics-containers.html" >}}