Detect gz program instead of using CMake module to check for gz-tools

[chapulina]

🦟 Bug fix

• Part of [tracker] Remove ignition-tools cmake check in Ignition software gazebo-tooling/release-tools#472

Summary

This branch was broken when gazebosim/gz-tools#96 was merged. This PR fixes the build by addressing gazebo-tooling/release-tools#472 like other libraries did.

Sorry for the disruption, I should have built the entire stack with the gz-tools PR instead of just a few libs.

Checklist

• 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

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