insights: capture group insights don't work when sub-repo permissions are enabled

looks like an issue with the internal actor user. site config settings:

```json
{
  "experimentalFeatures": {
    "subRepoPermissions": {
      "enabled": true
    }
}
```

live preview will work (user context) but backfill (ran with internal actor) will return no data.

/cc @joelkw @felixfbecker @vovakulikov