Design Canvas: Fixed issue with output variables being saved as local when the variable tab is active, JFS-8989.

Handwriiten node: Resolved issue with handwritten node failing and throwing an exception error, JFS-8984.

Document processing:

1. Fixed issues with checkboxes failing on specific documents, JFS-9008, JFS-8940.
2. Fixed issues with document screen showing blank for particular document, JFS-8876.

Doc reader node: Fixed issue with the Doc reader node failing for specific documents, JFS-8936.