Follow-up from "Use p_ci_job_artifacts table for exposed artifacts data" -- Stop using job.artifacts_paths in Evidences::BuildArtifactEntity

The following discussion from !199169 (merged) should be addressed:

• @lma-git started a discussion:

  I'm leaving this method artifacts_paths as is because it appears to be used outside of exposed artifacts here.

      expose :url, if: ->(job) { job.artifacts_paths.present? } do |job|
        download_project_job_artifacts_url(project, job)
      end

  I don't think it should be used for this entity though. If we delete a job's metadata (from archiving), it would make artifacts_paths.present? false, which could impact this feature. It looks like it's just testing for artifacts existence; we have other methods to accomplish this.

  I'm going to address this in a follow up issue.