[Sandbox] API returns error for card listing

[stevebissett]

Level: Medium see issue priorities

Describe the bug:

On the sandbox environment, the card listing endpoint returns an error when listing cards.

Steps To Reproduce:

1. In the Postman collection using PB Sandbox credentials.
2. Run the auth request
3. Execute the GET {{host}}/za/v1/cards
4. See error

Expected behaviour:

GET {{host}}/za/v1/cards

Expected Response Structure (from OpenAPI spec):

{
  "data": {
    "cards": [...]
  },
  "links": {...},
  "meta": {...}
}

Actual behaviour:

GET {{host}}/za/v1/cards

Actual Response Structure:

{
  "data": {
    "cards": "Error"
  },
  "links": {"self": null},
  "meta": {"totalPages": 1}
}

Additional context

• Verified in sandbox environment using Postman and with a Python client.