Inconsistent Implementation of Expansion Service spec

The external API implementations in Java and Python don’t add the PTransform to the components map along with the fake impulses of the ExpansionRequest. I didn’t notice this and was adding it to the component map while implementing the same in Go. Python expansion service had no problem with this while the Java expansion service failed and was the first to point this failure. It was a simple fix and a non blocker but points to a possible inconsistent implementation of the Expansion Service spec (whose details I am unaware of)?

Imported from Jira [BEAM-10795](https://issues.apache.org/jira/browse/BEAM-10795). Original Jira may contain additional context.
Reported by: kevinsijo.