[test] Fix flaky test TestQueues.testEagerPlanValidation

[BryanCutler]

Description

The TestQueues.testEagerPlanValidation is meant to trigger a plan validation failure in an async thread, but a race condition can occur if the query is created and the validation thread manages to complete before the trigger is set. Moving the trigger to be set before the query is created will ensure that it fails during validation.

Motivation and Context

Flaky test TestQueues.testEagerPlanValidation reported in #23838

Impact

Test Plan

Manually stopped main thread to simulate load and verified the race condition was fixed by moving the trigger.

Contributor checklist

• Please make sure your submission complies with our development, formatting, commit message, and attribution guidelines.
• PR description addresses the issue accurately and concisely. If the change is non-trivial, a GitHub Issue is referenced.
• Documented new properties (with its default value), SQL syntax, functions, or other functionality.
• If release notes are required, they follow the release notes guidelines.
• Adequate tests were added if applicable.
• CI passed.

Release Notes

Please follow release notes guidelines and fill in the release notes below.

== NO RELEASE NOTE ==