Fix UTF-8 error on search indexing
Fix UTF-8 error on search indexing

Upon indexing, Elasticsearch returned this error:

{
  "type": "action_request_validation_exception",
  "reason": "Validation Failed: 1: script or doc is missing;"
}

This happened because `json_encode` returned false, due to
an UTF-8 encoding error. Looks like `strtolower` has the
potential to malform UTF-8 strings.

art-institute-of-chicago/data-aggregator,art-institute-of-chicago/data-aggregator,art-institute-of-chicago/data-aggregator