chore: Make nats_client private at crate level, various tidy up (#4513)

Signed-off-by: Graham King <grahamk@nvidia.com>

lib/runtime/src/system_status_server.rs

@@ -636,7 +636,7 @@ mod integration_tests {
 
                 // Now create a namespace, component, and endpoint to make the system healthy
                 let namespace = drt.namespace("ns1234").unwrap();
-                let mut component = namespace.component("comp1234").unwrap();
+                let component = namespace.component("comp1234").unwrap();
 
                 // Create a simple test handler
                 use crate::pipeline::{async_trait, network::Ingress, AsyncEngine, AsyncEngineContextProvider, Error, ManyOut, SingleIn};
@@ -662,7 +662,6 @@ mod integration_tests {
                 // Start the service and endpoint with a health check payload
                 // This will automatically register the endpoint for health monitoring
                 tokio::spawn(async move {
-                    component.add_stats_service().await.unwrap();
                     let _ = component.endpoint(ENDPOINT_NAME)
                         .endpoint_builder()
                         .handler(ingress)

lib/runtime/tests/soak.rs

@@ -120,8 +120,7 @@ mod integration {
 
         // // make the ingress discoverable via a component service
         // // we must first create a service, then we can attach one more more endpoints
-        let mut component = runtime.namespace(DEFAULT_NAMESPACE)?.component("backend")?;
-        component.add_stats_service().await?;
+        let component = runtime.namespace(DEFAULT_NAMESPACE)?.component("backend")?;
         component
             .endpoint("generate")
             .endpoint_builder()