[23459] Fix/socket buffer size handling

[EugenioCollado]

Description

This task aims to fix:

• test_UDPv4Transport does not actually set the socket buffer size

• try_setting_buffer_size final attempt sets an upper limit for the buffer size that is not implemented in the main loop

This PR is a frontport of the proper changes from #5921

@Mergifyio backport 3.2.x

Contributor Checklist

• Commit messages follow the project guidelines.
• 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; 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).
• 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

• The PR has a milestone assigned.
• The title and description correctly express the PR's purpose.
• Check contributor checklist is correct.
• If this is a critical bug fix, backports to the critical-only supported branches have been requested.
• Check CI results: changes do not issue any warning.
• Check CI results: failing tests are unrelated with the changes.

[EugenioCollado]

@MiguelCompany failing test example_tests.custom_payload_pool seems unrelated