feat(quic): Wake transport when adding a new dialer or listener

[elenaf9]

Description

Wake quic::GenTransport if a new dialer or listener is added.

Notes

This re-adds #3306 with the solution initially drafted by @mxinden for waking the transport if a new dialer is added.
I added to also wake the transport if a new listener was pushed. The SelectAll around the listeners itself doesn't wake the task if a new element is pushed. This is not a major problem since the user would call poll again after a listen_on call and thus registering a new waker, but it solves the edge cast of a user doing something like this:

match quic_transport.poll_next(cx) {
   Poll::Ready(event) => return event,
   Poll::Pending => {}
}
quic_transport.listen_on(addr);
return Poll::Pending

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• .A changelog entry has been made in the appropriate crates

[mxinden]

Change looks good to me, minus the small suggestion below.

Thanks for putting more thought into this @elenaf9!

[mxinden]

Also can you add a short changelog entry? I forgot to add one in #3306 unfortunately.

[mergify]

This pull request has merge conflicts. Could you please resolve them @elenaf9? 🙏