Preload owner at Projects::PipelineSchedulesController#index

Description

https://gitlab.com/gitlab-org/gitlab-ce/blob/master/app/controllers/projects/pipeline_schedules_controller.rb#L11 includes last_pipeline, but owner

Proposal

Preload owner as well

Links / references

• https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/11307

/cc @zj