(Bug 59204) Properties do not unset on page deletion

Clean-up of related subjects to a property has to be done before store data
are modified which means that either run UpdateDispatcherJob before the
deleteSubject() in "online" mode or put both UpdateDispatcherJob and deleteSubject()
in a DeferredSubjectRemovalJob to ensure synchronize execution.

https://bugzilla.wikimedia.org/show_bug.cgi?id=59204