Replace owner with first_owner in various specs

spec/serializers/build_details_entity_spec.rb

spec/serializers/ci/lint/result_serializer_spec.rb

spec/serializers/diff_file_base_entity_spec.rb

spec/serializers/runner_entity_spec.rb

spec/serializers/trigger_variable_entity_spec.rb

spec/support/helpers/repo_helpers.rb

...ared_contexts/graphql/requests/packages_shared_context.rb

...mples/features/creatable_merge_request_shared_examples.rb

...ib/sidebars/projects/menus/zentao_menu_shared_examples.rb

...mples/models/update_project_statistics_shared_examples.rb

...ort/shared_examples/requests/api/notes_shared_examples.rb

spec/tasks/gitlab/backup_rake_spec.rb

spec/views/layouts/nav/sidebar/_project.html.haml_spec.rb

.../ci/external_pull_requests/create_pipeline_worker_spec.rb

spec/workers/cleanup_container_repository_worker_spec.rb

spec/workers/delete_container_repository_worker_spec.rb

spec/workers/delete_merged_branches_worker_spec.rb

spec/workers/post_receive_spec.rb

spec/workers/project_destroy_worker_spec.rb