Create organization risk model

curl --request POST \
  --url https://api.tilt.io/api/v1/custom/org/{organization_uuid}/risk_model \
  --header 'Content-Type: application/json' \
  --header 'X-Api-Key: <api-key>' \
  --data '{
  "risk_covariance": {
    "factors": [
      "<string>"
    ],
    "matrix": [
      [
        "<string>"
      ]
    ]
  },
  "risk_loadings": {
    "factors": [
      "<string>"
    ],
    "loadings": {}
  },
  "risk_idiosyncratic": {}
}'

{
  "risk_covariance": {
    "factors": [
      "<string>"
    ],
    "matrix": [
      [
        "<string>"
      ]
    ]
  },
  "risk_loadings": {
    "factors": [
      "<string>"
    ],
    "loadings": {}
  },
  "risk_idiosyncratic": {}
}