Diff

mod_presence: Send unavailable presence in current thread run `session:dispatch_stanza(pres)` enqueues processing of the stanza in the sessions async thread, but becasue the entire stream close handling is now in that thread it would process the presence after the stream and session was completely closed, leading to weird errors "sent to a resting session". We call core_process_stanza() since this is what :dispatch_stanza calls in the end.