Fix GPUClientYamlTestSuiteIT (elastic#139070)

Backport for elastic#138978

This test fails on release tests.

Add feature flag to this test

Author: mayya-sharipova

test/test-clusters/src/main/java/org/elasticsearch/test/cluster/FeatureFlag.java

@@ -25,7 +25,8 @@ public enum FeatureFlag {
         "es.index_dimensions_tsid_optimization_feature_flag_enabled=true",
         Version.fromString("9.2.0"),
         null
-    );
+    ),
+    GPU_FORMAT("es.gpu_vectors_indexing_feature_flag_enabled=true", Version.fromString("9.2.0"), null);
 
     public final String systemProperty;
     public final Version from;

x-pack/plugin/gpu/src/yamlRestTest/java/org/elasticsearch/xpack/gpu/GPUClientYamlTestSuiteIT.java

@@ -10,6 +10,7 @@
 
 import org.elasticsearch.gpu.GPUSupport;
 import org.elasticsearch.test.cluster.ElasticsearchCluster;
+import org.elasticsearch.test.cluster.FeatureFlag;
 import org.elasticsearch.test.rest.yaml.ClientYamlTestCandidate;
 import org.elasticsearch.test.rest.yaml.ESClientYamlSuiteTestCase;
 import org.junit.BeforeClass;
@@ -35,7 +36,8 @@ private static ElasticsearchCluster createCluster() {
             // Needed to get access to raw vectors from Lucene scorers
             .jvmArg("--add-opens=org.apache.lucene.core/org.apache.lucene.codecs.lucene99=org.elasticsearch.server")
             .jvmArg("--add-opens=org.apache.lucene.core/org.apache.lucene.codecs.hnsw=org.elasticsearch.server")
-            .jvmArg("--add-opens=org.apache.lucene.core/org.apache.lucene.internal.vectorization=org.elasticsearch.server");
+            .jvmArg("--add-opens=org.apache.lucene.core/org.apache.lucene.internal.vectorization=org.elasticsearch.server")
+            .feature(FeatureFlag.GPU_FORMAT);
 
         var libraryPath = System.getenv("LD_LIBRARY_PATH");
         if (libraryPath != null) {