Replace DebugString() with PrintToString() (backport #685)

[mergify]

Fixes some issues on Homebrew like this one.

Starting with v30, google protobuf DebugString() shows extra information besides the message content. You can see the explanation here. This patch updates our code replacing DebugString() with PrintToString().

Checklist

• Signed all commits for DCO
• Added tests
• Added example and/or tutorial
• 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
• 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.

---

This is an automatic backport of pull request #685 done by Mergify.

[mergify]

Cherry-pick of fbffc6f has failed:

On branch mergify/bp/ign-transport11/pr-685
Your branch is up to date with 'origin/ign-transport11'.

You are currently cherry-picking commit fbffc6f.
  (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 <file>..." to mark resolution)
	both modified:   example/subscriber_generic.cc
	both modified:   src/NodeShared.cc
	both modified:   src/Node_TEST.cc
	both modified:   src/cmd/gz.cc
	both modified:   src/cmd/gz.hh
	both modified:   src/cmd/gz_src_TEST.cc
	both modified:   src/cmd/service_main.cc
	both modified:   src/cmd/topic_main.cc
	both modified:   test/integration/twoProcsPubSubSubscriber_aux.cc
	both modified:   tutorials/04_messages.md

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]

resolving the conflicts generated by mergify was not easy for me here

I think it would have been easier to manually cherry-pick and then use git mergetool because that brings up a 3-way merge

maybe there's a way to open the conflicts generated by mergify in a 3-way view, but I don't know how