Null in list of providers

There is a null value in the list of providers being returned from the https://cmr.earthdata.nasa.gov/search/providers endpoint.

To replicate

```bash
curl -XGET https://cmr.earthdata.nasa.gov/search/providers | jq -c '.items[4]'
```

Compare to other entries
```bash
curl -XGET https://cmr.earthdata.nasa.gov/search/providers | jq -c '.items[3]'
```
