Fix credential fulfillment structure to be conformant with latest CM

[kimdhamilton]

• Structure now looks like below
• Also need to snapshot/version supported libraries
• Additional followup
  • credential-fulfillment.ts: repair after making consistent with latest Credential Manifest
  • credential-fulfillment.test.ts: duplicate tests?

  "credential_response": {
    "id": "a30e3b91-fb77-4d22-95fa-871689c322e2",
    "spec_version": "https://identity.foundation/credential-manifest/spec/v1.0.0/",
    "applicant": "did:example:123",
    "manifest_id": "32f54163-7166-48f1-93d8-ff217bdb0653",
    "application_id": "9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d",
    "fulfillment": {
      "descriptor_map": [
        {
          "id": "banking_output_2",
          "format": "jwt_vc",
          "path": "$.verifiableCredential[0]"
        },
        {
          "id": "employment_output",
          "format": "ldp_vc",
          "path": "$.verifiableCredential[1]"
        },
        {
          "id": "citizenship_output_1",
          "format": "ldp_vc",
          "path": "$.verifiableCredential[2]"
        }
      ]
    }
  },

[kimdhamilton]

fixed with #524