Vague error message in evaluate_process_from_url

[EmileSonneveld]

Now the error message is
Invalid process graph specified.
A message like this would explain the issue better:
Invalid process graph specified. process_id='BIOPAR' does not match result from namespace query: 'BIOPAR_V2'

{
  "process_graph": {
    "BIOPAR1": {
      "process_id": "BIOPAR",
      "arguments": {
        "biopar_type": "FAPAR",
        "date": [
          "2020-06-27",
          "2020-07-27"
        ],
        "polygon": {
          "type": "Polygon",
          "coordinates": [
            [
              [
                5.179324150085449,
                51.2498689148547
              ],
              [
                5.178744792938232,
                51.24672597710759
              ],
              [
                5.185289382934569,
                51.24504696935156
              ],
              [
                5.18676996231079,
                51.245342479161295
              ],
              [
                5.187370777130127,
                51.24918393390799
              ],
              [
                5.179324150085449,
                51.2498689148547
              ]
            ]
          ]
        }
      },
      "namespace": "https://openeo.dataspace.copernicus.eu/openeo/1.2/processes/u:3e24e251-2e9a-438f-90a9-d4500e576574/BIOPAR_V2"
    },
    "saveresult1": {
      "process_id": "save_result",
      "arguments": {
        "data": {
          "from_node": "BIOPAR1"
        },
        "format": "GTiff",
        "options": {}
      },
      "result": true
    }
  }
}

Issue found by @Pratichhya

[EmileSonneveld]

Will be fixed under Open-EO/openeo-api#515