Previously, image annotations for signature seals used a static yOffset
when combined with ink annotations, which caused positioning issues.
This change calculates the y-position of the signature annotation
relative to the next annotation and applies it only for the first seal.
- Added `yPosOfSigAnnot` calculation for precise vertical placement.
- Updated `AddInstantJSONAnnotationToPDF` to overwrite bbox.y for seals.
- Removed hardcoded ink offset logic.