Add release for CrossClustersCancellationIT

Author: smalyshev

x-pack/plugin/esql/src/internalClusterTest/java/org/elasticsearch/xpack/esql/action/CrossClustersCancellationIT.java

@@ -27,6 +27,7 @@
 import org.elasticsearch.xcontent.XContentBuilder;
 import org.elasticsearch.xcontent.json.JsonXContent;
 import org.elasticsearch.xpack.esql.plugin.ComputeService;
+import org.junit.After;
 import org.junit.Before;
 
 import java.util.ArrayList;
@@ -76,6 +77,11 @@ public void resetPlugin() {
         SimplePauseFieldPlugin.resetPlugin();
     }
 
+    @After
+    public void releasePlugin() {
+        SimplePauseFieldPlugin.release();
+    }
+
     @Override
     protected boolean reuseClusters() {
         return false;