fix: 🐛 fixed API error when using base64

[ianardee]

Fixed API error when using base64

Description

Force use of filename when using base64 input type to comply with the API.

Motivation and Context

mindee.http.HTTPException:
Receipt API 400 HTTP error: {"api_request": {"error": {"code": "BadRequest", "details": {"document": ["File must be one of binary file, URL or base64"]}, "message": "Invalid fields in form"}, "resources": [], "status": "failure", "status_code": 400, "url": "http://api.mindee.net/v1/products/mindee/expense_receipts/v3/predict"}}

How Has This Been Tested

Added unit test, updated tests to more easily detect this sort of problem in the future.

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[jonathanMindee]

Great thank you!