[native] Make EmojiThreadAvatarCreation work with activeThreadSelector

Summary:
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

Test Plan: I added an artificial delay on the keyserver side and confirmed that the loading spinner appears currently now (which was a regression introduced in D8021)

Reviewers: ginsu, atul

Reviewed By: atul

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D8023