pageserver: use PS node id for SK appname (#10522)

## Problem

This one is fairly embarrassing. Safekeeper node id was used in the
pageserver application name
when connecting to safekeepers.

## Summary of changes

Use the right node id.

Closes https://github.com/neondatabase/neon/issues/10461

pageserver/src/tenant/timeline/walreceiver/walreceiver_connection.rs

@@ -118,7 +118,7 @@ pub(super) async fn handle_walreceiver_connection(
     cancellation: CancellationToken,
     connect_timeout: Duration,
     ctx: RequestContext,
-    node: NodeId,
+    safekeeper_node: NodeId,
     ingest_batch_size: u64,
 ) -> Result<(), WalReceiverError> {
     debug_assert_current_span_has_tenant_and_timeline_id();
@@ -140,7 +140,7 @@ pub(super) async fn handle_walreceiver_connection(
 
     let (replication_client, connection) = {
         let mut config = wal_source_connconf.to_tokio_postgres_config();
-        config.application_name(format!("pageserver-{}", node.0).as_str());
+        config.application_name(format!("pageserver-{}", timeline.conf.id.0).as_str());
         config.replication_mode(tokio_postgres::config::ReplicationMode::Physical);
         match time::timeout(connect_timeout, config.connect(postgres::NoTls)).await {
             Ok(client_and_conn) => client_and_conn?,
@@ -162,7 +162,7 @@ pub(super) async fn handle_walreceiver_connection(
         latest_wal_update: Utc::now().naive_utc(),
         streaming_lsn: None,
         commit_lsn: None,
-        node,
+        node: safekeeper_node,
     };
     if let Err(e) = events_sender.send(TaskStateUpdate::Progress(connection_status)) {
         warn!("Wal connection event listener dropped right after connection init, aborting the connection: {e}");