Endpoint /api/metadata/validate - some wrong request status codes or validation statuses

[pmbinapps]

Occurred during exploration endpoint in #876

To reproduce use endpoint url = 'https://test-sanchonet.govtool.byron.network/api/metadata/validate'
with input as for specific case:

NOT OK, TBC - response is 200, status is null but hash is not for provided json, for case: URL to other json (drep format), hash ok - expected: INCORRECT_JSONLD
Inputs:
 {
    "url": "https://github.com/mpawel79/testrepo/blob/master/PawelDrep.jsonld",
    "hash": "eebfff0e2213ff0c5331e6d9d99d47a5a825dce7053671b6ed4daae4b4e0df5e"
}
Response code: 200
{
    "status": null,
    "valid": false,
    "raw": {
        "valid": true
    }
}
--------------------

NOT OK - response not ok, status not ok, for case: valid URL to corrupted json, hash ok - expected: INCORRECT_JSONLD
Inputs:
 {
    "url": "https://raw.githubusercontent.com/mpawel79/testrepo/master/test_INVALID_JSON_FORMAT.jsonld",
    "hash": "eebfff0e2213ff0c5331e6d9d99d47a5a825dce7053671b6ed4daae4b4e0df5e"
}
Response code: 200
{
    "status": null,
    "valid": false,
    "raw": {
        "valid": true
    }
}
--------------------


NOT OK - response ok, status not given - some other error msg, for INCORRECT_HASH not resturned,  URL ok, corrupted hash to long: expected: INCORRECT_HASH
Inputs:
 {
    "url": "https://raw.githubusercontent.com/mpawel79/testrepo/master/InfoJune03.jsonld",
    "hash": "CORRUPTED_eebfff0e2213ff0c5331e6d9d99d47a5a825dce7053671b6ed4daae4b4e0df5e"
}
Response code: 400
{
    "combinator": "ReqBody'",
    "error": "Error in $.hash: mzero"
}
--------------------

[MSzalowski]

That endpoint is not to be used by govtool. We can close that issue as not planned.