Fix gradle run on Serverless (elastic#105938)

On Serverless it is not possible to configure deprecation indexing (it
is always off). This commit updates the behaviour of
`ElasticsearchCluster` to no longer attempt to configure deprecation
indexing on stateless nodes.

build-tools/src/main/java/org/elasticsearch/gradle/testclusters/ElasticsearchCluster.java

@@ -433,7 +433,7 @@ private void commonNodeConfig() {
             if (node.getTestDistribution().equals(TestDistribution.INTEG_TEST)) {
                 node.defaultConfig.put("xpack.security.enabled", "false");
             } else {
-                if (node.getVersion().onOrAfter("7.16.0")) {
+                if (hasDeprecationIndexing(node)) {
                     node.defaultConfig.put("cluster.deprecation_indexing.enabled", "false");
                 }
             }
@@ -474,13 +474,17 @@ public void nextNodeToNextVersion() {
         commonNodeConfig();
         nodeIndex += 1;
         if (node.getTestDistribution().equals(TestDistribution.DEFAULT)) {
-            if (node.getVersion().onOrAfter("7.16.0")) {
+            if (hasDeprecationIndexing(node)) {
                 node.setting("cluster.deprecation_indexing.enabled", "false");
             }
         }
         node.start();
     }
 
+    private static boolean hasDeprecationIndexing(ElasticsearchNode node) {
+        return node.getVersion().onOrAfter("7.16.0") && node.getSettingKeys().contains("stateless.enabled") == false;
+    }
+
     @Override
     public void extraConfigFile(String destination, File from) {
         nodes.all(node -> node.extraConfigFile(destination, from));