Upgrade async-tungstenite to tokio (#26193)

We're seeing panics caused by a buggy implementation of AsyncWrite
that is being passed to rustls: 

https://github.com/rustls/rustls/issues/2316#issuecomment-2662838186

One hypothesis was that we're using (comparatively) non-standard async
tools for connecting over websockets; so this attempts to make us be
(comparitvely) more standard.

Release Notes:

- N/A

crates/rpc/src/peer.rs

@@ -1030,7 +1030,7 @@ mod tests {
         let _ = messages_ended_rx.await;
         assert!(
             server_conn
-                .send(WebSocketMessage::Binary(vec![]))
+                .send(WebSocketMessage::Binary(vec![].into()))
                 .await
                 .is_err()
         );