Fix more instances of gz-cmake4

[chapulina]

🦟 Bug fix

• Follow up to https://github.com/gazebosim/gz-cmake/pull/296
• Part of https://github.com/gazebo-tooling/release-tools/issues/578

Summary

More instances noticed by @jennuine .

That's why we need our examples to be compiled with our test suite 🙃

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)
• [x] 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.

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[chapulina]

• 298