[21313] Allow all @default annotation values for unions

[EduPonz]

Description

This PR enables the use of any @default annotation value for unions.
Depends on:

• [21313] Allow all @default annotation values for unions IDL-Parser#152

Required by:

• [21313] Type propagation policy Fast-DDS#5081

Contributor Checklist

• Commit messages follow the project guidelines.
• 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: 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

• 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]

We should add a test case for this here

[MiguelCompany]

LGTM with green CI