Brave has a feature called joint spans that was enabled by default with
Spring Cloud Sleuth (and Boot 2.x). This has changed with
Micrometer Tracing and Boot 3.x. In order to make migration simpler,
joint spans should be set through a property.
This is a Brave+B3-only feature, W3C is not supported by Brave and
OTel does not have this capability.
See gh-35165