Bump urllib3 from 2.2.3 to 2.6.0 in /samples/client/echo_api/python (#22496)

Bumps [urllib3](https://github.com/urllib3/urllib3) from 2.2.3 to 2.6.0.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/main/CHANGES.rst)
- [Commits](urllib3/urllib3@2.2.3...2.6.0)

---
updated-dependencies:
- dependency-name: urllib3
  dependency-version: 2.6.0
  dependency-type: direct:production
...

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Author: dependabot[bot]