Collection export: adds empty file,field_linked_agent

[jefferya]

The MODS to Workbench CSV process for a collection sometimes adds an extraneous field_linked_agent relators:ive:person: causing the Workbench ingest to fail on the collection item

Symfony\Component\HttpKernel\Exception\UnprocessableEntityHttpException: Unprocessable Entity: validation failed. field_linked_agent.0.target_id: This value should be of the correct primitive type. in Drupal\rest\Plugin\rest\resource\EntityResource->validate() (line 55 of /var/www/drupal/web/core/modules/rest/src/Plugin/rest/resource/EntityResourceValidationTrait.php).

Sample item and output data:

id,parent_id,field_member_of,url_alias,title,field_alternative_title,field_model,field_resource_type,langcode,field_classification,field_coordinates,field_coordinates_text,field_description,field_description_long,field_dewey_classification,field_display_hints,field_display_title,field_edition,field_edtf_date,field_edtf_date_created,field_edtf_date_issued,field_extent,field_genre,field_geographic_subject,field_identifier,field_isbn,field_language,field_lcc_classification,field_local_identifier,field_main_banner,field_note,field_oclc_number,field_physical_form,field_pid,field_place_published,field_rights,field_subject,field_subjects_name,field_table_of_contents,field_temporal_subject,field_weight,file,field_linked_agent

tpatt:8b08f5a5-79f0-4aff-bce2-d0aa437484c5,,3,/islandora/object/tpatt:8b08f5a5-79f0-4aff-bce2-d0aa437484c5,4. TPatT - Interviews,,Collection,Collection,,,,,,,,,,,,,,,,,,,eng,,,,,,,tpatt:8b08f5a5-79f0-4aff-bce2-d0aa437484c5,,,,,,,,,relators:ive:person: `