Convert DAG to Use GraphQL

What does this MR do?

This MR converts the DAG Visualization graph to use GraphQL as part of &3640. The backend was handled in !36900 (merged).

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.

Related issue: #223263 (closed).