Fix MAGN-5082 Dynamo does not notice if a change (delete or move) has occurred to an import instance

<h4>Summary</h4>

Originally element binding is not implemented for the ImportInstance node. I think this is reasonable. Just imagine after you get the original import instance, how could you set it to a new file or body. The only way is to import it again.

But since there is no trace information for this element, there is no way for the node to know when the import instance has been changed or deleted as the link between nodes and elements is obtained through trace information.

So I am adding the trace information to fix the issue.

@pboyer 
PTAL