Bump selenium from 4.20.0 to 4.21.0 in /docker/py3-native (#26561)

Bumps [selenium](https://github.com/SeleniumHQ/Selenium) from 4.20.0 to 4.21.0.
- [Release notes](https://github.com/SeleniumHQ/Selenium/releases)
- [Commits](SeleniumHQ/selenium@selenium-4.20.0...selenium-4.21.0)

---
updated-dependencies:
- dependency-name: selenium
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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