Disable failing Manager_Test on windows

[Blast545]

Summary

Disables a test failing on windows, follows the same approach applied to a newer branch here: https://github.com/gazebosim/gz-launch/pull/249

Reference build: https://build.osrfoundation.org/job/gz_launch-6-win/52/

Checklist

• [x] Signed all commits for DCO
• [ ] 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)
• [ ] While waiting for a review on your PR, please help review another open pull request to support the maintainers

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

[Blast545]

:farmer: Pr-job on windows was taking a long time, and given that this PR is not particularly risky I decided to abort that build in favor of taking a look to the gz-launch6 CI after merging the PR.