frauddetection uses child span for messaging

[puckpuck]

Changes

With #1538, the accountingservice moved from a child span to a linked span from the Kafka queue. We no longer had any child spans from Kafka. This change will set the fraud detection service to generate child spans from Kafka, allowing the demo to showcase both use cases from messaging queues.

Merge Requirements

For new features contributions please make sure you have completed the following
essential items:

• CHANGELOG.md updated to document new feature additions
  * [ ] Appropriate documentation updates in the docs
  * [ ] Appropriate Helm chart updates in the helm-charts

Maintainers will not merge until the above have been completed. If you're unsure
which docs need to be changed ping the
@open-telemetry/demo-approvers.

[julianocosta89]

Not sure if we should add this.
AFAIK the recommended way to do it is via linked spans, as we are doing now.

https://opentelemetry.io/docs/specs/semconv/messaging/messaging-spans/#topic-with-multiple-consumers

[puckpuck]

I don't see the example listed there, but I believe a child span should be created for single producer/consumer scenarios. I understand we don't have that scenario here at all, but being able to demonstrate trace propagation using a child span is still something I think we should showcase.

[julianocosta89]

All examples in the page use link.
The recommendation by the Messaging SIG is using link: #1538 (comment)