Remove example_INSTALL_DIR from PREFIX_PATH on examples

[j-rivero]

🦟 Bug fix

Summary

Remove the example_INSTALL_DIR to be passed to CMAKE_PREFIX_PATH since it is probably unused since the separator is wrong (semicolon instead of a colon). This triggered my attention since Noble has a warning with 3.28 CMake version.

CMake Warning:
  Ignoring extra path from command line:

   "/home/jenkins/workspace/gz_cmake-ci-gz-cmake3-noble-amd64/build/install/RelWithDebInfo"

CMake Warning:
  Ignoring extra path from command line:

   "/home/jenkins/workspace/gz_cmake-ci-gz-cmake3-noble-amd64/build/install/RelWithDebInfo"

CMake Warning:
  Ignoring extra path from command line:

   "/home/jenkins/workspace/gz_cmake-ci-gz-cmake3-noble-amd64/build/install/Release"

CMake Warning:
  Ignoring extra path from command line:

   "/home/jenkins/workspace/gz_cmake-ci-gz-cmake3-noble-amd64/build/install/Release"

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.