on nuxeo-user-suggestion, selected user shows up blank

happens on workflows and on audit

when one selects one user, it gets selected but the text where its username should be is empty.

the reason for this is that on some cases, the user object returned by the server doesnt have the field "entity type"
on these, cases, it is going to the "default" case where it tries to print the object as a string instead of a field of the object.

it should instead check if it is an object and if yes, print one field (id or display label) if is not object , then print all as a string.