Loading notes in Epics is broken

The refactor in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/29733 caused loading of notes in Epics to be broken because there's no project.

Failure/Error:
        notes = NotesFinder.new(project, current_user, finder_params_for_issuable).execute
                    .inc_relations_for_view
                    .includes(:noteable)
                    .fresh

      NameError:
        undefined local variable or method `project' for #<Groups::EpicsController:0x00007f941c866160>
        Did you mean?  project_url
        Did you mean?  project_url