Fix etcd_events not getting upgraded in upgrade-cluster.yml (#8550)

Signed-off-by: Mac Chaffee <me@macchaffee.com>

upgrade-cluster.yml

@@ -69,7 +69,7 @@
       tags: etcd
       vars:
         etcd_cluster_setup: true
-        etcd_events_cluster_setup: false
+        etcd_events_cluster_setup: "{{ etcd_events_cluster_enabled }}"
       when: not etcd_kubeadm_enabled | default(false)
 
 - hosts: k8s_cluster