Set up serverless network policy before setting up index (#4250)

Signed-off-by: Hai Yan <[email protected]>

data-prepper-plugins/opensearch/src/main/java/org/opensearch/dataprepper/plugins/sink/opensearch/OpenSearchSink.java

@@ -228,6 +228,10 @@ private void doInitializeInternal() throws IOException {
           .add(pluginSetting.getName()).toString());
       dlqWriter = potentialDlq.isPresent() ? potentialDlq.get() : null;
     }
+
+    // Attempt to update the serverless network policy if required argument are given.
+    maybeUpdateServerlessNetworkPolicy();
+
     indexManager.setupIndex();
 
     final Boolean requireAlias = indexManager.isIndexAlias(configuredIndexAlias);
@@ -257,9 +261,6 @@ private void doInitializeInternal() throws IOException {
             bulkRequestSupplier,
             pluginSetting);
 
-    // Attempt to update the serverless network policy if required argument are given.
-    maybeUpdateServerlessNetworkPolicy();
-
     objectMapper = new ObjectMapper();
     this.initialized = true;
     LOG.info("Initialized OpenSearch sink");