GH-2927: Subclasses for EmbeddedKafkaBroker param

Fixes: #2927

Starting a test without spring context with Embeded Lafka without `kraft` enabled and `EmbeddedKafkaZKBroker` as a test's parameter results in an exception:
```
No ParameterResolver registered for parameter [org.springframework.kafka.test.EmbeddedKafkaZKBroker broker] in method [public void test.SomeTest.test(org.springframework.kafka.test.EmbeddedKafkaZKBroker)].
org.junit.jupiter.api.extension.ParameterResolutionException: No ParameterResolver registered for parameter [org.springframework.kafka.test.EmbeddedKafkaZKBroker broker] in method [public void test.SomeTest.test(org.springframework.kafka.test.EmbeddedKafkaZKBroker)].
```
For test config:
```
@Test
public void test(EmbeddedKafkaZKBroker broker)
```

* Fix `EmbeddedKafkaCondition` to use `EmbeddedKafkaBroker.class.isAssignableFrom(parameterContext.getParameter().getType());` instead of just `parameterContext.getParameter().getType().equals(EmbeddedKafkaBroker.class)`

spring-kafka-test/src/main/java/org/springframework/kafka/test/condition/EmbeddedKafkaCondition.java

@@ -54,6 +54,7 @@ import org.springframework.util.StringUtils;
  * @author Artem Bilan
  * @author Pawel Lozinski
  * @author Adrian Chlebosz
+ * @author Michał Padula
  *
  * @since 2.3
  *
@@ -72,7 +73,7 @@ public class EmbeddedKafkaCondition implements ExecutionCondition, AfterAllCallb
 			return false;
 		}
 		else {
-			return parameterContext.getParameter().getType().equals(EmbeddedKafkaBroker.class);
+			return EmbeddedKafkaBroker.class.isAssignableFrom(parameterContext.getParameter().getType());
 		}
 	}
 

spring-kafka-test/src/test/java/org/springframework/kafka/test/condition/EmbeddedKafkaConditionTests.java

@@ -21,11 +21,14 @@ import static org.assertj.core.api.Assertions.assertThat;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.kafka.test.EmbeddedKafkaBroker;
+import org.springframework.kafka.test.EmbeddedKafkaZKBroker;
 import org.springframework.kafka.test.context.EmbeddedKafka;
 import org.springframework.kafka.test.utils.KafkaTestUtils;
 
 /**
  * @author Gary Russell
+ * @author Michał Padula
+ *
  * @since 2.3
  *
  */
@@ -41,4 +44,9 @@ public class EmbeddedKafkaConditionTests {
 		assertThat(broker.getPartitionsPerTopic()).isEqualTo(3);
 	}
 
+	@Test
+	public void testResolver(EmbeddedKafkaZKBroker broker) {
+		assertThat(broker).isNotNull();
+	}
+
 }