Revert ExecutorService change

In PregelBootstrap we depend on the released version (2.4.5).
This change will come when we release 2.4.6.

Author: Mats-SX

examples/pregel-bootstrap/src/test/java/gds/example/ExamplePregelComputationAlgoTest.java

@@ -64,7 +64,7 @@ void runExamplePregelComputation() {
             graph,
             config,
             new ExamplePregelComputation(),
-            ExecutorServices.DEFAULT,
+            Pools.DEFAULT,
             ProgressTracker.NULL_TRACKER
         );