NPE on DefaultMessage setBody if deprecated constructor was used

After upgrade camel 2.20.0, some operations fail with a NullPointerException:

Caused by: java.lang.NullPointerException
        at org.apache.camel.impl.MessageSupport.setBody(MessageSupport.java:122)

The issue seems to be introduced with the change CAMEL-11380.

The issue could be easily reproduced by using the deprecated constructor, where no camelContext is set:

        Message message = new DefaultMessage();
        message.setBody("something");

To remain better backward compatibility, i would suggest a nullcheck in the setBody for cases where the CamelContext is not set.