Removed the `[HttpGet("sign/test")]` endpoint and its `Test`
method from the `PdfSignatureController`. This method
contained hardcoded Base64 PDF data and predefined signing
options for testing purposes. Eliminated the associated
logic for decoding the Base64 string, creating signing
options, signing the PDF, and returning the signed file.
These changes streamline the controller by removing
unnecessary and potentially insecure functionality,
ensuring cleaner and more production-ready code.