[19315] Allow participant profiles with no rtps tag (backport #3771)

[mergify]

This is an automatic backport of pull request #3771 done by Mergify.
Cherry-pick of 9bcd313 has failed:

On branch mergify/bp/2.11.x/pr-3771
Your branch is up to date with 'origin/2.11.x'.

You are currently cherry-picking commit 9bcd31322.
  (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)

Changes to be committed:
	modified:   src/cpp/rtps/xmlparser/XMLParser.cpp
	new file:   test/unittest/xmlparser/regressions/simple_participant_profiles_nok.xml
	new file:   test/unittest/xmlparser/regressions/simple_participant_profiles_ok.xml

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   test/unittest/xmlparser/XMLParserTests.cpp

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

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[EduPonz]

@richiprosima please test this

[JesusPoderoso]

@richiprosima please test this

[JesusPoderoso]

@EduPonz I think CI issues are not related to this PR backport content. Could you confirm this?

[JesusPoderoso]

@EduPonz friendly ping

[EduPonz]

@EduPonz friendly ping

They definitely aren't. Merging this