`jwks` examples are missing the `keys` element

[awoie]

There are two examples of JWKS that don't have the keys element that is required by RFC7517. This should be fixed.

In https://openid.github.io/OpenID4VCI/openid-4-verifiable-credential-issuance-1_1-wg-draft.html#appendix-A.1.1.4

{
  "jwks": [
    {
      "kid": "urn:ietf:params:oauth:jwk-thumbprint:sha-256:mlUpog7vEewFBem6Ul09
       c2dtTwc8dFzVpIDX3sqGWW0",
      "kty": "EC",
      "crv": "P-256",
      "alg": "ES256",
      "x": "_LC1FTUl0MltKAOQzXNsofVMpWFV2obLGrNCat_CQ-g",
      "y": "kBjoyjNuMVAOq--qVUgylDoLKuMdk4imS-Kk5ahuYIU"
    }
  ]
}

and in https://openid.github.io/OpenID4VCI/openid-4-verifiable-credential-issuance-1_1-wg-draft.html#appendix-I.1

  "credential_request_encryption": {
    "jwks": [
      {
        "kty":"EC", "kid":"ac", "use":"enc", "crv":"P-256", "alg":"ECDH-ES",
        "x":"YO4epjifD-KWeq1sL2tNmm36BhXnkJ0He-WqMYrp9Fk",
        "y":"Hekpm0zfK7C-YccH5iBjcIXgf6YdUvNUac_0At55Okk"
      }
    ],