Checkstyle fixes

Author: raulavila

spring-rabbit/src/main/java/org/springframework/amqp/rabbit/support/DefaultMessagePropertiesConverter.java

@@ -33,7 +33,6 @@
 import org.springframework.amqp.core.MessageProperties;
 import org.springframework.util.CollectionUtils;
 import org.springframework.util.StringUtils;
-import org.springframework.util.NumberUtils;
 
 /**
  * Default implementation of the {@link MessagePropertiesConverter} strategy.
@@ -45,6 +44,7 @@
  * @author Artem Bilan
  * @author Ngoc Nhan
  * @author Johan Kaving
+ * @author Raul Avila
  *
  * @since 1.0
  */
@@ -148,13 +148,11 @@ else if (MessageProperties.RETRY_COUNT.equals(key)) {
 		if (target.getRetryCount() == 0) {
 			List<Map<String, ?>> xDeathHeader = target.getXDeathHeader();
 			if (!CollectionUtils.isEmpty(xDeathHeader)) {
-				Object countValue = xDeathHeader.get(0).get("count");
+				Object value = xDeathHeader.get(0).get("count");
 
-				if(countValue != null) {
-					target.setRetryCount(
-							NumberUtils.convertNumberToTargetClass((Number) countValue, Long.class));
+				if (value instanceof Number numberValue) {
+					target.setRetryCount(numberValue.longValue());
 				}
-
 			}
 		}