Implement missing RP test cases 28, 53, and 110

[giovanni-riela]

Motivation and Context

This Pull Request implements three missing Relying Party (RP) conformance test cases (RPR-028, RPR-053, and RPR-110), as identified in the missing_tests_rp.md tracking document. These additions enhance the presentation conformance suite by covering key security and protocol validation steps:

• RPR-028 (response_code entropy): Verifies that the response_code issued by the RP provides at least 32 characters of entropy using a URL-safe character set.
• RPR-053 (SD-JWT integrity): Ensures the RP correctly identifies and rejects authorization responses where the SD-JWT Key Binding JWT (KB-JWT) signature has been tampered with.
• RPR-110 (HTTP 200 on success): Explicitly validates that the RP returns an HTTP 200 status code when a valid authorization response is successfully submitted to the response_uri.

By implementing these tests, we provide more robust validation for RPs integrated with the IO Wallet ecosystem, ensuring they adhere to the required security standards and protocol specifications.