32345100 - Add Topic Link window is blank if the table includes any unassigned topic

Before

The following issue occurred only in the 9.1.0.1 release when there was a topic with a null Assigned to value.

When the topic workflow configuration was configured such that the topic's Assigned to field was filterable but not required, and the Add Topic Link table would have included an unassigned topic, then the Add Topic Link window was blank.

After

The Add Topic Link window displays correctly.