Preview USSD-PUSH request

curl --request POST \
  --url https://api.clickpesa.com/third-parties/payments/preview-ussd-push-request \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "amount": "<string>",
  "currency": "TZS",
  "orderReference": "<string>",
  "checksum": "<string>"
}'

{
  "activeMethods": [
    {
      "name": "<string>",
      "status": "AVAILABLE",
      "fee": 123,
      "message": 123
    }
  ]
}