`src config` commands fail

Created by: dadlerj

• Sourcegraph version: 3.15.1+

Reported by https://app.hubspot.com/contacts/2762526/company/557693052

Run src config list and src config get on against sourcegraph.com or a 3.15.1+ instance. I haven't tested against older versions.

GraphQL errors:
[
  {
    "locations": [
      {
        "column": 9,
        "line": 8
      }
    ],
    "message": "Fragment \"ConfigurationSubjectFields\" cannot be spread here as objects of type \"SettingsSubject\" can never be of type %!q(\u003cnil\u003e)."
  },
  {
    "locations": [
      {
        "column": 40,
        "line": 15
      }
    ],
    "message": "Unknown type \"ConfigurationSubject\"."
  },
  {
    "locations": [
      {
        "column": 13,
        "line": 20
      }
    ],
    "message": "Fragment \"ConfigurationFields\" cannot be spread here as objects of type %!q(\u003cnil\u003e) can never be of type \"Configuration\"."
  },
  {
    "locations": [
      {
        "column": 13,
        "line": 23
      }
    ],
    "message": "Fragment \"UserFields\" cannot be spread here as objects of type %!q(\u003cnil\u003e) can never be of type \"User\"."
  }
]