In D8021, we changing how our loading status worked. Before that the custom key name was not thread specific, but afterwards it is.
In the new system, for `EditThreadAvatarProvider` to know which `threadID` to look up, it calls `activeThreadSelector` on the nav state. For this to work, we need two things to be true:
1. The React Navigation route needs to be in `routeNames` in `route-names.js`
2. The React Navigation route params should have a field called `threadInfo`
This diff makes both changes so that the loading detection works
Depends on D8022