Fix: upgrade cluster discovery kubeconfig not found

When installing or upgrading in the past, there was no validation
config. Check if the file exists first to prevent subsequent validation
errors.

Signed-off-by: ChengHao Yang <17496418+tico88612@users.noreply.github.com>

roles/kubernetes/kubeadm/tasks/main.yml

@@ -58,6 +58,11 @@
   delegate_to: "{{ groups['kube_control_plane'] | first }}"
   when: kubeadm_use_file_discovery
 
+- name: Check if discovery kubeconfig exists
+  stat:
+    path: "{{ kube_config_dir }}/cluster-info-discovery-kubeconfig.yaml"
+  register: cluster_info_discovery_kubeconfig
+
 - name: Copy discovery kubeconfig
   copy:
     dest: "{{ kube_config_dir }}/cluster-info-discovery-kubeconfig.yaml"
@@ -66,7 +71,7 @@
     mode: "0644"
   when:
     - ('kube_control_plane' not in group_names)
-    - not kubelet_conf.stat.exists
+    - not kubelet_conf.stat.exists or not cluster_info_discovery_kubeconfig.stat.exists
     - kubeadm_use_file_discovery
 
 - name: Create kubeadm client config