Review fixes for rocketmq-client-4.8:library (open-telemetry#17658)

Co-authored-by: otelbot <197425009+otelbot@users.noreply.github.com>

Author: otelbot[bot]

instrumentation/rocketmq/rocketmq-client-4.8/library/src/main/java/io/opentelemetry/instrumentation/rocketmqclient/v4_8/MapSetter.java

@@ -8,6 +8,7 @@
 import io.opentelemetry.context.propagation.TextMapSetter;
 import javax.annotation.Nullable;
 import org.apache.rocketmq.client.hook.SendMessageContext;
+import org.apache.rocketmq.common.message.Message;
 
 final class MapSetter implements TextMapSetter<SendMessageContext> {
 
@@ -16,6 +17,10 @@ public void set(@Nullable SendMessageContext carrier, String key, String value)
     if (carrier == null) {
       return;
     }
-    carrier.getMessage().getProperties().put(key, value);
+    Message message = carrier.getMessage();
+    if (message == null) {
+      return;
+    }
+    message.getProperties().put(key, value);
   }
 }

instrumentation/rocketmq/rocketmq-client-4.8/library/src/main/java/io/opentelemetry/instrumentation/rocketmqclient/v4_8/RocketMqProducerAttributeGetter.java

@@ -85,7 +85,11 @@ public Long getBatchMessageCount(SendMessageContext request, @Nullable Void unus
 
   @Override
   public List<String> getMessageHeader(SendMessageContext request, String name) {
-    String value = request.getMessage().getProperties().get(name);
+    Message message = request.getMessage();
+    if (message == null) {
+      return emptyList();
+    }
+    String value = message.getProperties().get(name);
     if (value != null) {
       return singletonList(value);
     }