Fix N+1 in v3 builds API

The N+1 issue was caused by loading the job_artifacts_archive for each
job (build) individually. Including that in the builds
AssociationRelation fixed the issue.

lib/api/v3/builds.rb

@@ -35,8 +35,7 @@ module API
         get ':id/builds' do
           builds = user_project.builds.order('id DESC')
           builds = filter_builds(builds, params[:scope])
-
-          present paginate(builds), with: ::API::V3::Entities::Build
+          present paginate(builds.includes(:job_artifacts_archive)), with: ::API::V3::Entities::Build
         end
 
         desc 'Get builds for a specific commit of a project' do