chore: move test file into __tests__

[pauldambra]

I came to my PR and couldn't publish locally because there's a test file outside of the tests folder

i'm too lazy to figure out why we can't support test files in src and only in src/tests`

so i moved it

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Name	Status	Preview	Updated (UTC)
posthog-js	✅ Ready (Inspect)	Visit Preview	Sep 16, 2024 10:33am

[github-actions]

Size Change: 0 B

Total Size: 1.21 MB

ℹ️ View Unchanged

Filename	Size
dist/array.full.js	346 kB
dist/array.js	162 kB
dist/exception-autocapture.js	10.4 kB
dist/main.js	163 kB
dist/module.js	162 kB
dist/recorder-v2.js	110 kB
dist/recorder.js	111 kB
dist/surveys-preview.js	59.8 kB
dist/surveys.js	66 kB
dist/tracing-headers.js	8.26 kB
dist/web-vitals.js	10.3 kB

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