[BUG] UI metadata not getting filtered out during API calls

[ohltyler]

Describe the bug
A clear and concise description of what the bug is.

The logic here is supposed to filter out unnecessary UI metadata when the request is coming directly from a user via an API call, rather than from Kibana, however this is not happening:

Example:

curl localhost:9200/_opendistro/_anomaly_detection/detectors/<id>?pretty
...
    "ui_metadata" : {
      "features" : {
...

Expected behavior is that no UI metadata is returned in this case.