Clean unnecessary 'attachToDocument' in 'spec/frontend/pipelines'

Summary

As described in &2419 (closed), we need to clean up our Jest tests from unnecessary attachToDocument usage

Risks

No risks

Involved specs

• spec/frontend/pipelines/graph/action_component_spec.js
• spec/frontend/pipelines/graph/job_item_spec.js
• spec/frontend/pipelines/graph/linked_pipeline_spec.js
• spec/frontend/pipelines/pipeline_triggerer_spec.js
• spec/frontend/pipelines/pipeline_url_spec.js