- Added the `ConversionWithSameMimeTypeException` to handle cases where document conversion is requested for the same MIME type.
- Updated `StoredObjectToPdfConverter` to throw the new exception when encountering such cases.
- Enhanced error logging in `PostSendExternalMessageHandler` to capture these specific conversion errors.
Enhanced the `addConvertedVersion` method in `StoredObjectToPdfConverter` to optionally include converted content in the response. Updated `SignatureRequestController` to handle non-PDF documents by converting them to PDF before processing the signature request.
Introduced the StoredObjectToPdfConverter service to handle conversion of stored objects to PDF format. Added unit tests to ensure proper functionality, including versioning and exception handling.
