proxy: Fix cancellations (#7510)

## Problem

Cancellations were published to the channel, that was never read.

## Summary of changes

Fallback to global redis publishing.

proxy/src/bin/proxy.rs

@@ -339,7 +339,7 @@ async fn main() -> anyhow::Result<()> {
 
     let cancel_map = CancelMap::default();
 
-    let redis_publisher = match &regional_redis_client {
+    let redis_publisher = match &redis_notifications_client {
         Some(redis_publisher) => Some(Arc::new(Mutex::new(RedisPublisherClient::new(
             redis_publisher.clone(),
             args.region.clone(),