Move scheduling of periodic updater so it is run by both SE and MP, not just SE (helidon-io#3733)

Signed-off-by: tim.quinn@oracle.com <tim.quinn@oracle.com>

Author: tjquinno

metrics/metrics/src/main/java/io/helidon/metrics/MetricsSupport.java

@@ -412,6 +412,8 @@ protected void postConfigureEndpoint(Routing.Rules defaultRules, Routing.Rules s
             io.helidon.metrics.RegistryFactory fullRF = (io.helidon.metrics.RegistryFactory) rf;
             Registry app = fullRF.getARegistry(MetricRegistry.Type.APPLICATION);
 
+            PeriodicExecutor.start();
+
             // register the metric registry and factory to be available to all
             MetricsContextHandler metricsContextHandler = new MetricsContextHandler(app, rf);
             defaultRules.any(metricsContextHandler);
@@ -468,8 +470,6 @@ private void setUpFullFeaturedEndpoint(Routing.Rules serviceEndpointRoutingRules
      */
     @Override
     public void update(Routing.Rules rules) {
-        PeriodicExecutor.start();
-
         configureEndpoint(rules, rules);
     }