fix: reject fake secrets manager startup errors

Co-authored-by: pascal-botpress <179493770+pascal-botpress@users.noreply.github.com>

Author: Copilot

cdk-postgresql/test/fixtures/fake-secrets-manager.ts

@@ -39,7 +39,19 @@ export const startFakeSecretsManager = () => {
     });
   });
 
-  return new Promise<Server>((resolve) => {
-    server.listen(SECRETS_MANAGER_PORT, () => resolve(server));
+  return new Promise<Server>((resolve, reject) => {
+    const onListening = () => {
+      server.removeListener("error", onError);
+      resolve(server);
+    };
+
+    const onError = (error: Error) => {
+      server.removeListener("listening", onListening);
+      reject(error);
+    };
+
+    server.once("error", onError);
+    server.once("listening", onListening);
+    server.listen(SECRETS_MANAGER_PORT);
   });
 };