[BE] Make dependency path data available for the vulnerability details page

Make dependency path data available for the vulnerability details page. This will unblock the FE issue: [FE] Integrate with API data for vulnerability ... (#519967 - closed)

Implementation Plan

1. (Depends on GraphQL query for component dependency path (!182289 - merged))
2. backend add Vulnerability.dependency_paths method for fetching paths via Sbom::DependencyPath model or finder
3. backend Update VulnerabilityEntity with dependency_paths key
4. backend will expose paths via vulnerability.dependency_paths