[21077] Update Fast DDS docs QoS examples

[cferreiragonz]

Description

This PR reviews that the API of QoS is identical for all entities that share a common QoS. It also makes the PropertyPolicyQoS of DataWriters and DataReader unmutable (such as the one of Participants), until a deeper study is made on what Policies should be mutable on enabled entities.

• Python tests has also been updated: [21077] Update Fast DDS docs QoS examples Fast-DDS-python#145

Contributor Checklist

• Commit messages follow the project guidelines.
• 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)
• ❌ Changes are backport compatible: they do NOT break ABI nor change library core behavior.
• ❌ Changes are API compatible.
• N/A 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.
  • Related documentation PR: [21077] Update Fast DDS docs QoS examples Fast-DDS-docs#781
• 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.

[Tempate]

LGTM with green CI

[Tempate]

LGTM