Fix flake in test_automation_listener_receives_notifications_and_processes_them

[devin-ai-integration]

This PR removes a race in test_automation_listener_receives_notifications_and_processes_them, which failed on main with assert 2 == 3 (the automation__created call was missing) in this run.

The test started listen_for_automation_changes() as a task and then slept 0.1 seconds before it created the automation. Postgres sends a NOTIFY only to connections that already run LISTEN, so the notification is lost, not delayed, if the listener is not subscribed yet. On a loaded runner, the asyncpg connect plus reconcile_automations() can take more than 0.1 seconds, so the created notification was lost and the retry_asserts loop could not recover it.

The test now sends probe notifications with a random automation ID until the listener reports one. This proves the LISTEN is registered before the test makes real automation changes. The assertions filter the recorded calls by the automation ID, so a probe that arrives late cannot change the result.

Verification

• Reproduced the CI failure locally with Postgres 14: with an added 1 second delay in the listener connection setup, the old test failed with the same missing-created assertion, and the new test passed.
• Ran the module 20 times against Postgres: all passed.
• Ran tests/events/server/models with --numprocesses auto --maxprocesses 6 --dist worksteal: 39 passed.

Checklist

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[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no bugs or issues to report.