[20652] Improve filtering of DNS tests

[MiguelCompany]

Description

When both PKCS#11 and DNS tests had to be disabled, the filter expression for gtest was incorrectly generated.
This made Ubuntu and MacOS CI on github fail.

Additionally, this PR fixes the commands used to detect whether the DNS local entries for the corresponding tests have been added, and adds some related informational messages to the CMake files.

@Mergifyio backport 2.13.x

Contributor Checklist

• Commit messages follow the project guidelines.
• N/A The code follows the style guidelines of this project.
• N/A Tests that thoroughly check the new feature have been added/Regression tests checking the bug and its fix have been added; the added tests pass locally
• N/A Any new/modified methods have been properly documented using Doxygen.
• Changes are ABI compatible.
• Changes are API compatible.
• N/A New feature has been added to the versions.md file (if applicable).
• N/A New feature has been documented/Current behavior is correctly described in the documentation.
• Applicable backports have been included in the description.

Reviewer Checklist

• The PR has a milestone assigned.
• The title and description correctly express the PR's purpose.
• Check contributor checklist is correct.
• Check CI results: changes do not issue any warning.
• Check CI results: failing tests are unrelated with the changes.

[MiguelCompany]

@richiprosima Please test this

[EduPonz]

@Mergifyio backport 2.13.x

[mergify]

backport 2.13.x

✅ Backports have been created

• #4619 [20652] Improve filtering of DNS tests (backport #4603) has been created for branch 2.13.x