Fix Global Embedded Kafka sample for current Spring Boot

* We don't need to worry about `spring.embedded.kafka.brokers` since Embedded Kafka
populates `spring.kafka.bootstrap-servers` as well

Author: artembilan

samples/sample-05/README.adoc

@@ -7,11 +7,13 @@ Additional properties for the underlying `GlobalEmbeddedKafkaTestExecutionListen
 
 Run only `./mvnw test` command for this sample.
 The Maven will report to the output similar two log messages:
-```
+
+[source,text]
+----
 11:03:44.383 [main] INFO  o.s.k.t.j.GlobalEmbeddedKafkaTestExecutionListener - Started global Embedded Kafka on: 127.0.0.1:53671
 ...
 11:03:48.439 [main] INFO  o.s.k.t.j.GlobalEmbeddedKafkaTestExecutionListener - Stopped global Embedded Kafka.
-```
+----
 One in the beginning of the test plan - and another in the end before reporting failures.
 
 The application by itself is going to fail because it has a configuration like `spring.kafka.bootstrap-servers=${spring.embedded.kafka.brokers}`.

samples/sample-05/src/main/resources/application.properties

@@ -1,4 +1,3 @@
-spring.kafka.bootstrap-servers=${spring.embedded.kafka.brokers}
 spring.kafka.producer.properties[max.block.ms]=1000
 spring.kafka.consumer.auto-offset-reset=earliest
 logging.level.root=error

samples/sample-05/src/test/java/com/example/Sample05Application1Tests.java

@@ -29,7 +29,7 @@
 import org.springframework.test.annotation.DirtiesContext;
 
 /**
- * This test is going to fail from IDE since there is no exposed {@code spring.embedded.kafka.brokers} system property.
+ * This test is going to fail from IDE since there is no exposed {@code spring.kafka.bootstrap-servers} system property.
  * Use Maven to run tests which enables global embedded Kafka broker via properties provided to Surefire plugin.
  */
 @ExtendWith(OutputCaptureExtension.class)

samples/sample-05/src/test/java/com/example/Sample05Application2Tests.java

@@ -30,7 +30,7 @@
 import org.springframework.test.annotation.DirtiesContext;
 
 /**
- * This test is going to fail from IDE since there is no exposed {@code spring.embedded.kafka.brokers} system property.
+ * This test is going to fail from IDE since there is no exposed {@code spring.kafka.bootstrap-servers} system property.
  * This test demonstrates that global embedded Kafka broker config for {@code auto.create.topics.enable=false}
  * is in an effect - the topic {@code nonExistingTopic} does not exist on the broker.
  * See {@code /resources/kafka-broker.properties} and Maven Surefire plugin configuration.