[native] Dispatch SET_DATA_LOADED action after registration completes

Summary:
Same as the previous diff, but for register instead of siweAuth. Copying description from there:

We want to prevent registerActionTypes.success from directly setting dataLoaded, so that in the new registration flow on native we can defer LoggedOutModal and RegistrationNavigator from being dismissed until after the avatar server call completes.

Instead of having registerActionTypes.success directly set dataLoaded, we'll use this new action instead. A later diff will update reduceDataLoaded so that registerActionTypes.success no longer affects it.

Depends on D8109

Test Plan: Tested registration (SIWE and otherwise) flows on native and web

Reviewers: atul, ginsu

Reviewed By: atul

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D8110