`isMain` filter doesn't work when requesting media studios through activity.

[N0D4N]

Let's say i want to get only studios that are main for media from activity and i have simple query like this

{
  Activity(id: 259350345) {
    ... on ListActivity {
      media {
        id #885
        studios(isMain: true) {
          nodes {
            name
          }
        }
      }
    }
  }
}

Query above will return all studios for given media even so some aren't main, as you can see judging by query below, when we request studios directly from media

{
  Media(id: 885) {
    studios {
      edges{
        isMain
        node{
          name
        }
      }
    }
  }
}