fix: flaky test informerStoppedHandlerShouldBeCalledWhenInformerStops (#1777)

Author: csviri

operator-framework-core/src/test/java/io/javaoperatorsdk/operator/processing/event/source/informer/InformerEventSourceTest.java

@@ -248,6 +248,7 @@ void filtersOnDeleteEvents() {
   @Test
   void informerStoppedHandlerShouldBeCalledWhenInformerStops() {
     try {
+      ConfigurationServiceProvider.reset();
       final var exception = new RuntimeException("Informer stopped exceptionally!");
       final var informerStoppedHandler = mock(InformerStoppedHandler.class);
       ConfigurationServiceProvider