was/client: remove the obsolete pool reference from SubmitPendingResponse()
was/client: remove the obsolete pool reference from SubmitPendingResponse()

Now that the destructor gets called, we can rely on `DestructObserver`.

CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy