Inconsistent Behavior in Hiding Child Actors

Pressing the 'h' key only hides the root actor and none of the children, unlike the scene outliner where clicking the eye icon hides the root actor and all children.

This appears to be because edactHideSelected does not enumerate an actors' attached actors or child actors.

1. Create a UE project with at least 2 actors, and nest one of them as a child actor of the other
2. Click the "eye" hide button for the parent, and notice both actors are hidden
3. Click again to reveal, then select the parent and press 'h'
4. The children and parent are now hidden, pressing H again will show the hierarchy