[20953] Fix Proxy block in TypeLookup Service

[cferreiragonz]

Description

This PR fixes two minor data races and solves a bugfix in which the Proxy Pool was running out of Proxies due multiple requests of the TypeLookup Service. Now, if the type is not known, a copy of the Proxy is made to avoid blocking the discovery.

Contributor Checklist

• [X] Commit messages follow the project guidelines.
• [X] 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.
• N/A Any new configuration API has an equivalent XML API (with the corresponding XSD extension)
• [X] Changes are backport compatible: they do NOT break ABI nor change library core behavior.
• [X] 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.
• N/A Applicable backports have been included in the description.

Reviewer Checklist

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

[cferreiragonz]

@richiprosima please test this

[cferreiragonz]

@richiprosima please test_3 this