[21758] Fix structs TypeObject registration with -typeros2 option

[juanlofer-eprosima]

Description

Structs are currently registered in the type object registry with their scoped name, instead of using their ROS 2 scoped name when typeros2 is provided. As a consequence, there is a discrepancy between the name with which the type is registered in the type object registry and the name embedded in the generated TypeSupport.

Contributor Checklist

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• 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.
• Applicable backports have been included in the description.

Reviewer Checklist

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• Check CI results: failing tests are unrelated with the changes.