[8.19] (backport #10819) Always run the otel collector self-monitoring input in the otel runtime

internal/pkg/agent/application/monitoring/component/testdata/monitoring_config_full_process.yaml

@@ -865,7 +865,8 @@ inputs:
         target: component
   type: http/metrics
   use_output: monitoring
-- data_stream:
+- _runtime_experimental: otel
+  data_stream:
     namespace: default
   id: metrics-monitoring-collector
   name: metrics-monitoring-collector

internal/pkg/agent/application/monitoring/component/v1_monitor.go

@@ -578,14 +578,19 @@ func (b *BeatsMonitor) injectMetricsInput(
 				"namespace": monitoringNamespace,
 			},
 			"streams": []any{prometheusStream},
+			// hardcode this to run in the otel runtime
+			// it won't work in a beat process because we don't set the required environment variable there
+			"_runtime_experimental": monitoringCfg.OtelRuntimeManager,
 		})
 	}
 
 	// Make sure we don't set anything until the configuration is stable if the otel manager isn't enabled
 	if b.config.C.RuntimeManager != monitoringCfg.DefaultRuntimeManager {
 		for _, input := range inputs {
 			inputMap := input.(map[string]interface{})
-			inputMap["_runtime_experimental"] = b.config.C.RuntimeManager
+			if _, found := inputMap["_runtime_experimental"]; !found {
+				inputMap["_runtime_experimental"] = b.config.C.RuntimeManager
+			}
 		}
 	}