WikiCreatingEvent is not part of the observationContext during the wiki initialization of subwiki creation

The creation of a subwiki is framed by two events WikiCreatingEvent and WikiCreatedEvent: it's normally possible to detect that we are in the creation of a subwiki by checking if the ObservationContext is in WikiCreatingEvent.
However, during the creation of a subwiki we're triggering its initialization, which is done in a WikiInitializationJob performed in its own thread, and apparently during that initialization the ObservationContext is empty: we cannot see that we're inside a WikiCreatingEvent.

The consequence of that is that a listener triggered during the initialization of the wiki cannot skip the execution based on WikiCreatingEvent which can be a problem in some cases.