Merge branch '59546-fix-error-handling-for-missing-domain' into 'master'

Fix Auto DevOps missing domain error handling

Closes #59546

See merge request gitlab-org/gitlab-ce!26627

changelogs/unreleased/59546-fix-error-handling-for-missing-domain.yml

+---
+title: Fix Auto DevOps missing domain error handling
+merge_request: 26627
+author:
+type: fixed

lib/gitlab/ci/templates/Auto-DevOps.gitlab-ci.yml

@@ -856,7 +856,7 @@ rollout 100%:
   function check_kube_domain() {
     ensure_kube_ingress_base_domain
 
-    if [ -z ${KUBE_INGRESS_BASE_DOMAIN+x} ]; then
+    if [[ -z "$KUBE_INGRESS_BASE_DOMAIN" ]]; then
       echo "In order to deploy or use Review Apps,"
       echo "AUTO_DEVOPS_DOMAIN or KUBE_INGRESS_BASE_DOMAIN variables must be set"
       echo "From 11.8, you can set KUBE_INGRESS_BASE_DOMAIN in cluster settings"