Reduce StopWatch_TEST.py sleep times (backport #800)

[mergify]

🦟 Bug fix

Ports #326 to python

Summary

The sleep durations in Stopwatch_TEST.cc were reduced in #326, but the python test still takes nearly 20 seconds. This updates the python test to match the sleep durations used in c++, reducing the duration to 1 second:

• https://build.osrfoundation.org/job/gz_math-ci-pr_any-homebrew-arm64/230/testReport/gz-math.src.python_pybind11.test.StopWatch_TEST/history/

Backport Policy

• This is safe to backport to the following versions:
  • Jetty
  • Ionic
  • Harmonic
  • Fortress
• This should not be backported
• I am not sure
• Other (fill in yourself)

Checklist

• Signed all commits for DCO
• Added a screen capture or video to the PR description that demonstrates the fix (as needed)
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• Updated Bazel files (if adding new files). Created an issue otherwise.
• While waiting for a review on your PR, please help review another open pull request to support the maintainers
• Was GenAI used to generate this PR? If so, make sure to add "Assisted-by" to your commits. (See this policy for more info.)

Assisted-by: Gemini Next

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by and Generated-by messages.

Backports: If this is a backport, please use Rebase and Merge instead.

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This is an automatic backport of pull request #800 done by [Mergify](https://mergify.com).