Unsuported options field prompt as string

For example this .json raises an error:

{
    "git_base_url": "https://github.com/ai4os-hub",
    "open_source_license": ["MIT", "Apache 2.0", "BSD-3-Clause", "No license file"],

    "__prompts__": {
        "git_base_url": "Some text",
        "open_source_license": "Some text"
    }
}

Error:

Exception has occurred: AttributeError
'str' object has no attribute 'get'
  File "/home/borja/projects/cookiecutter-web/backend/app/utils.py", line 52, in parse_field
    data["prompt"] = prompt.get("__prompt__", None) if prompt else None
                     ^^^^^^^^^^
  File "/home/borja/projects/cookiecutter-web/backend/app/utils.py", line 33, in parse_fields
    data[name] = parse_field(name, value, prompts.get(name, None))
  File "/home/borja/projects/cookiecutter-web/backend/app/api_v1/endpoints/project.py", line 84, in fetch_fields
    return utils.parse_fields(data)
  File "<string>", line 1, in <module>
AttributeError: 'str' object has no attribute 'get'

Basically it means it was expecting a dict and not a string as the prompt. How to form it is the one at the documentation. From https://cookiecutter.readthedocs.io/en/stable/advanced/human_readable_prompts.html

{
    "package_name": "my-package",
    "linting": ["ruff", "flake8", "none"],
    "__prompts__": {
        "package_name": "Select your package name",
        "linting": {
            "__prompt__": "Which linting tool do you want to use?",
            "ruff": "Ruff",
            "flake8": "Flake8",
            "none": "No linting tool"
        }
    }
}

Where the "lintin" is a sub json with "prompt" inside.

However, cookicutter seems to work without any problem when the prompt is just a string and not a json. Therefore probably the best is to also provide support for this feature or at least provide a more informative error.