Detach a preview background file from a project template.

DELETE /data/project-templates/{template_id}/preview-background-files/{preview_background_file_id}
Jwt authorization
DELETE /data/project-templates/{template_id}/preview-background-files/{preview_background_file_id} 
curl \
 --request DELETE 'http://api.example.com/data/project-templates/{template_id}/preview-background-files/{preview_background_file_id}' \
 --header "Authorization: $API_KEY"