Test: recover search index tool it in multi node cluster (opensearch-…

…project#2407) (opensearch-project#2796)

plugin/build.gradle

@@ -192,14 +192,6 @@ integTest {
     // Set this to true this if you want to see the logs in the terminal test output.
     // note: if left false the log output will still show in your IDE
     testLogging.showStandardStreams = true
-
-    // Exclude integration test for search index tool for multiple nodes
-    // because we cannot get concrete exception message in multi-node cluster
-    if (_numNodes > 1) {
-        filter {
-            excludeTestsMatching "org.opensearch.ml.rest.RestSearchIndexToolIT.*"
-        }
-    }
 }
 
 testClusters.integTest {