Revert "upgrade opensearch cluster after working around opensearch-pr…

…oject/opensearch-k8s-operator#759 (comment) elifesciences/issues#8911"

This reverts commit 82ccb5d.

kustomizations/search/app/opensearch/cluster.yaml

@@ -8,11 +8,11 @@ spec:
   general:
     serviceName: opensearch
     serviceAccount: opensearch
-    version: 2.16.0
+    version: 2.11.0
     monitoring:
       enable: false
     pluginsList:
-    - "https://github.com/aiven/prometheus-exporter-plugin-for-opensearch/releases/download/2.16.0.0/prometheus-exporter-2.16.0.0.zip"
+    - "https://github.com/aiven/prometheus-exporter-plugin-for-opensearch/releases/download/2.11.0.0/prometheus-exporter-2.11.0.0.zip"
     - "repository-s3"
     snapshotRepositories:
     - name: ${aws_backup_s3_bucket}
@@ -26,7 +26,7 @@ spec:
     - name: aws-iam-token
       path: /usr/share/opensearch/config/aws-iam-token
   dashboards:
-    version: 2.16.0
+    version: 2.11.0
     enable: true
     replicas: 1
     resources: