Remove useless attachToDocument usage in spec/frontend

What does this MR do?

As described in &2419 (closed), cleans up our Jest tests from unnecessary attachToDocument usage

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

Conformity

• Merge request performance guidelines
• Style guides

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.

Closes: #196764 (closed)