layer1: add namespace summary active helper

pkg/utils/namespace_manager_model.go

@@ -81,6 +81,10 @@ type NamespaceManagerSummary struct {
 	Subscribers     []string
 }
 
+func (summary NamespaceManagerSummary) HasActiveNamespaces() bool {
+	return summary.LiveNamespaces > 0
+}
+
 type ManagedNamespaceWatcherConfig struct {
 	Component       string
 	Namespaces      []string