[NFC] Assert something in unit test

[demeritcowboy]

Overview

When I wrote this in #24586 it was just to demonstrate the fail. But then when I redid the PR against 5.54 and added the fix, I forgot to update the test to make an assertion of some kind.

Civi has beStrictAboutTestsThatDoNotTestAnything set to false in phpunit.xml. I'm not sure if that's intentional but normally such a test would have passed but been flagged as "risky".

[civibot]

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