The commit restructures the ChromaVectorStore builder pattern to use a no-args constructor
with fluent API for setting the ChromaApi.
This change:
- Makes builder creation consistent with other vector stores
- Moves ChromaApi validation to the doValidate method
- Improves builder API ergonomics
The change requires updating all builder usages to use the new .chromaApi() method instead
of passing it in the constructor.
e2825c9877