improve lazy creation of accounts related nodes

Core/src/org/sleuthkit/autopsy/datamodel/accounts/Accounts.java

@@ -147,6 +147,14 @@ final public class Accounts implements AutopsyVisitableItem {
      */
     private abstract class ObservingChildren<X> extends Children.Keys<X> {
 
+        /**
+         * Override of default constructor to force lazy creation of nodes, by
+         * concrete instances of ObservingChildren
+         */
+        ObservingChildren() {
+            super(true);
+        }
+
         /**
          * Create of keys used by this Children object to represent the child
          * nodes.