Use GTEST_SKIP in unsupported tests (backport #604)

[mergify]

🦟 Bug fix

Part of gazebosim/gz-rendering#1235

Summary

While checking whether gz-sensors tests are using ogre2 on macOS, I noticed that very few tests are using GTEST_SKIP() for unsupported engines, so this switches the gzdbg stream then return pattern to stream directly to GTEST_SKIP() as is done in gz-rendering.

On Ubuntu, this shows an increase of 1 skipped test:

• DistortionCameraSensor/DistortionCameraSensorTest.ImagesWithBuiltinSDF/ogre2

On macOS, there are many new skipped tests due to the removal of ogre1.9 in osrf/homebrew-simulation#3394 (see follow-up work in #605).

This also fixes a segfault of INTEGRATION_dvl when the render engine plugin fails to load, which also started failing on macOS when ogre1.9 was removed in osrf/homebrew-simulation#3394.

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 "Generated-by" to your commits. (See this policy for more info.)

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.

---

This is an automatic backport of pull request #604 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of fc58044 has failed:

On branch mergify/bp/ign-sensors6/pr-604
Your branch is up to date with 'origin/ign-sensors6'.

You are currently cherry-picking commit fc58044.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	both modified:   test/integration/boundingbox_camera.cc
	both modified:   test/integration/camera.cc
	both modified:   test/integration/depth_camera.cc
	both modified:   test/integration/distortion_camera.cc
	deleted by us:   test/integration/dvl.cc
	both modified:   test/integration/gpu_lidar_sensor.cc
	both modified:   test/integration/rgbd_camera.cc
	both modified:   test/integration/segmentation_camera.cc
	both modified:   test/integration/thermal_camera.cc
	deleted by us:   test/integration/triggered_boundingbox_camera.cc
	both modified:   test/integration/triggered_camera.cc
	deleted by us:   test/integration/wide_angle_camera.cc

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[scpeters]

I resolved conflicts

[scpeters]

we don't have GTEST_SKIP in our vendored gtest on fortress; let's skip this