Read top-level dependency ancestors from direct graph edges

Ryan Wellsrequested to merge
rw/593156-path-finder-top-level-from-edges into master

What does this MR do and why?

PathFinder now reads top-level ancestors from the direct edges it already loads, removing one query per call. This is behind the default-off dependency_paths_top_level_ancestors_from_direct_edges flag. Once rolled out, BuildDependencyGraph can stop writing transitive rows (~41% of sbom_graph_paths on GitLab.com), which is done in !257733.

Related to #593156

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Edited by Ryan Wells

Merge request reports