JavaScript: Remove `AdditionalFeature` from `ApiGraphs`.
JavaScript: Remove `AdditionalFeature` from `ApiGraphs`.

I ended up not using it for flow summaries, so at this point it is purely speculative generality. We can reintroduce it later if we need to.

github/codeql,github/codeql,github/codeql,github/codeql,github/codeql,github/codeql,github/codeql,github/codeql,github/codeql,github/codeql,github/codeql,github/codeql,github/codeql,github/codeql,github/codeql