[lib] Don't sync users with non-authoritative keyservers

Summary:
We can take a similar approach to what we do with threads that are being hashed - inform the server that there are no inconsistencies. This is a kind of hack, but it will be later improved when we start syncing the store between clients - then the keyserver will no longer attempt the sync.

https://linear.app/comm/issue/ENG-7132/stop-performing-state-sync-of-users-and-current-user-with-non

Test Plan:
Check if the state sync still works for one keyserver - modify keyserver DB and check if the state is fixed.
Connect to the second keyserver and check if the state difference doesn't cause an update on client side - modified username on the authoritative keyserver and checked if the name remains changed after state sync with the second keyserver.

Reviewers: inka, kamil, michal, varun

Reviewed By: inka

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D11271