Use cert from metadata to validate response

[niwsa]

What does this PR do?

• Fixes an issue where the SAML response without an X509 certificate causes an 'Invalid Assertion error.' With Return the certs/public keys in the parsed metadata saml20#435 we now store the cert inside the idpMetadata. The stored cert will be used to validate the SAML response (will fallback to thumbprint otherwise).
• The saved trace will now include the specific error message.

Type of change

• Updated dependencies
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How should this be tested?

• Existing unit tests

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code and corrected any misspellings
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[ghost]

👇 Click on the image for a new way to code review

Legend