Pipeline Graph Structural Update: Menu Bugfix

What does this MR do?

Fixes an issue where the parallel job dropdown would not toggle off. See: &5260 (closed)

Screenshots (strongly suggested)

Before

After

Does this MR meet the acceptance criteria?

Conformity

• Code review guidelines
• 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.
• Tested in all supported browsers

Related to #276949 (closed), &5260 (closed)