refactor(clickhouse): Streamline query task initiation

[Twixes]

Problem

Currently our query initiation behavior is a bit different in tests and outside of them. Only in production do we use transaction.on_commit.

Changes

Let's be consistent between tests and prod.

How did you test this code?

Just needs all the tests to pass.

[Twixes]

Unfortunately it seems while transaction.on_commit generally can be tested, here this isn't quite working. Might not be worth a deeper investigation.

[posthog-bot]

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