Add runners GraphQL query

What does this MR do?

This MR adds a runners top-level GraphQL query behind the :runner_graphql_query FF. I am not yet very familiar with pagination support in GraphQL, so when reviewing it'd probably be a good idea to keep that in mind in case something is missing.

Screenshots (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

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

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Closes #328518 (closed)