Workflows; Workflow Type Items; Changing the Document on an Item of Type "Send Document" could cause an error

If a User edited the Document Id for a "Send Document" Workflow Item on a Workflow Type, an "Object reference not set to an instance of an Object" error could occur when:

1. An invalid Document Id was entered.
2. Once the field was automatically cleared, another character is entered.

This has now been fixed and the Document Id can now be changed as expected.