presence: subscribe *after* publish

If we simply rely on the timeout of the subscribe, it starts too early,
and the previously allocted port is not freed yet, thus the subscribe
no longer starts - this commit fixes this race

presence/01.presence/scenario.yml

@@ -29,6 +29,10 @@ tasks:
       subscriber: testing2
     calls: 1
     require:
-      started:
+      after:
         task: Publish
-        wait: 2
+<<<<<<< Updated upstream
+        wait: 2
+=======
+        wait: 1
+>>>>>>> Stashed changes