AutoDevops fix ensure_namespace() does not explicitly test namespace

changelogs/unreleased/ensure_namespace.yml

+---
+title: AutoDevops function ensure_namespace() now explicitly tests the namespace
+merge_request: 29567
+author: Jack Lei
+type: fixed

lib/gitlab/ci/templates/Jobs/Deploy.gitlab-ci.yml

@@ -505,7 +505,7 @@ rollout 100%:
   }
 
   function ensure_namespace() {
-    kubectl describe namespace "$KUBE_NAMESPACE" || kubectl create namespace "$KUBE_NAMESPACE"
+    kubectl get namespace "$KUBE_NAMESPACE" || kubectl create namespace "$KUBE_NAMESPACE"
   }
 
   function check_kube_domain() {