top10: 1.2.1 - (GREEN) Made the aggregation state accessible

* The assertion, regarding the expected state, is true for both tests.
* The assertion, regarding the expected messages, ix only true for the
  test that is based on the `TopologyTestDriver`.
* _This highlights the need for an additional integration test to avoid
  misinterpretation of the results of tests, that are based on the
  ``TopologyTestDriver``.
* _Note,_ that the assertion, regarding the expected state, works as
  well in the `Top10ApplicationIT`, if the output buffering is enabled,
  because the changed state becomes visible immediately.
* The buffering ist still turned of, so that the disabled test can be
  run in IntelliJ to comprehend, that the assertion is actually false.