vici: List additional information for deleted CHILD_SAs

vici: List additional information for deleted CHILD_SAs

If a CHILD_SA is terminated, the updown event is triggered after the
CHILD_SA is set to state CHILD_DELETED, so no usage stats or detail
information like SPIs were reported.  However, when an IKEv2 SA is
terminated, the updown event for its children is triggered without
changing the state first, that is, they usually remain in state
INSTALLED and detailed data was reported in the event.  IKEv1
CHILD_SAs are always terminated individually, i.e. with state
change and no extra data so far.

With this change usage stats are also returned for individually deleted
CHILD_SAs as long as the SA has not yet expired.

Fixes #3198.