Clean unnecessary 'attachToDocument' in various specs in 'spec/frontend'

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/boards/issue_card_spec.js
• spec/frontend/cycle_analytics/limit_warning_component_spec.js
• spec/frontend/jobs/components/erased_block_spec.js
• spec/frontend/releases/detail/components/app_spec.js
• spec/frontend/notes/components/discussion_actions_spec.js