Issue Summary

Assets import creates duplicate Objects if an object-type attribute is an Identifier and the value is empty in source file

Steps to Reproduce

1. Create 2 Object Types A and B. In OT "A" , add Object attribute to "B"
2. Create an import configuration for OT "A" with Name and 'Object' type.
3. Select Both Name and object-referenced-attribute as 'Identifier'.
4. Create a CSV file where this object-referenced-attribute value is empty.
5. Import the CSV file.

Expected Results

Object Should be Updated based on the file.

Actual Results

A duplicate object is created (since the Identifier condition failed).

Workaround

• Do not mark an object-referenced-attribute as an 'Identifier'. 
• Make sure to have a value for the object-referenced attribute if it's marked as an 'Identifier'