Increase client timeout on CCS tests (elastic#75346)

Increase the client timeout for CCS tests that are occasionally
timing out.

Author: bpintea

x-pack/plugin/eql/qa/common/src/main/java/org/elasticsearch/test/eql/RemoteClusterAwareEqlRestTestCase.java

@@ -30,6 +30,8 @@
 
 public abstract class RemoteClusterAwareEqlRestTestCase extends ESRestTestCase {
 
+    private static final long CLIENT_TIMEOUT = 40L; // upped from 10s to accomodate for max measured throughput decline
+
     // client used for loading data on a remote cluster only.
     private static RestClient remoteClient;
 
@@ -82,7 +84,7 @@ protected static RestClient clientBuilder(Settings settings, HttpHost[] hosts) t
     }
 
     protected static TimeValue timeout() {
-        return TimeValue.timeValueSeconds(10);
+        return TimeValue.timeValueSeconds(CLIENT_TIMEOUT);
     }
 
     // returned client is used to load the test data, either in the local cluster (for rest/javaRestTests) or a remote one (for