Ensure `ClientAttestationJWT` is a valid Wallet Instance Attestation per TS3

[dzarras]

When using ClientAuthentication.AttestationBased, besides checking that the provided JWT is a valid Client Attestation JWT, we must also ensure that it is a valid Wallet Instance Attestation per TS3.

To that end we must verify the contents and ensure the presence and structure of eudi_wallet_info.

Reference: https://github.com/eu-digital-identity-wallet/eudi-doc-standards-and-technical-specifications/blob/main/docs/technical-specifications/ts3-wallet-unit-attestation.md#23-content

[dzarras]

Relates to #482