Use database for dependencies API

What does this MR do and why?

Get data from Sbom::Occurrence records rather than reading gl-dependency-scanning-report.json. This should significantly improve the performance of the API, as currently we need to read and parse the entirety of the JSON report artifacts even if we are only showing 1 page of results.

MR acceptance checklist

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Screenshots or screen recordings

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How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Import this project: https://gitlab.com/gitlab-org/govern/threat-insights-demos/verification-projects/verify-408846-group/verify-408849-project
2. Enable the feature flag echo 'Feature.enable(:use_database_for_dependencies_api)' | bundle exec rails c
3. Run a pipeline on the project and wait for it to complete
4. Go to <gdk_url>/api/v4/:project_id/dependencies
5. Dependencies are rendered