Bump tornado from 6.0.3 to 6.4.1 in /tests/functional_tests (#53)

Bumps [tornado](https://github.com/tornadoweb/tornado) from 6.0.3 to 6.4.1.
- [Changelog](https://github.com/tornadoweb/tornado/blob/master/docs/releases.rst)
- [Commits](tornadoweb/tornado@v6.0.3...v6.4.1)

---
updated-dependencies:
- dependency-name: tornado
  dependency-type: direct:production
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

tests/functional_tests/requirements.txt

@@ -1,4 +1,4 @@
 numpy==1.22.4
 python-dotenv==0.21.0
 scikit-learn==1.1.2
-tornado==6.0.3
+tornado==6.4.1