[15321] Adding DomainParticipantFactory::get_shared_instance() API

[MiguelCompany]

Description

This PR addresses #2537 by adding a new API on DomainParticipantFactory that returns a shared pointer, and making the old API call the new one and return the raw pointer inside the shared one.

Contributor Checklist

• [x] Commit messages follow the project guidelines.
• [x] The code follows the style guidelines of this project.
• [ ] Tests that thoroughly check the new feature have been added/Regression tests checking the bug and its fix have been added.
• [x] Any new/modified methods have been properly documented using Doxygen.
• [ ] Fast DDS test suite has been run locally.
• [ ] Changes are ABI compatible.
• [x] Changes are API compatible.
• [ ] Documentation builds and tests pass locally.
• [ ] New feature has been added to the versions.md file (if applicable).
• [ ] New feature has been documented/Current behavior is correctly described in the documentation.

Reviewer Checklist

• [ ] Check contributor checklist is correct.
• [ ] Check CI results: changes do not issue any warning.
• [ ] Check CI results: failing tests are unrelated with the changes.