fix: Wallet Attestation response code and method

[grausof]

This PR aligns the Wallet Attestation request with the REST specification

[fmarino-ipzs]

Please, add the normative text according to the non normative examples

[grausof]

Please, add the normative text according to the non normative examples

Can you give an example? Originally there was no other additional text

[peppelinux]

Please, add the normative text according to the non normative examples

Can you give an example? Originally there was no other additional text

During the weekly meeting we agreed that along with the non normative example we need to better clarify the beahviour of the implementations using normative language and clear definition about the requirements these must satisfy

therefore we decided that this PR requires normative language within the appropriate section describing the result represented in the non normative examples