[identity] Move Logout and DeleteUser RPCs

Summary:
Moved Logout and DeleteUser RPCs to the authenticated proto. Updated client calls accordingly.

Depends on D9930

Test Plan: Verified that logout is callable via auth client. Verified that DeleteUser deletes item from users table (called this in native commRustModule to verify client working)

Reviewers: varun

Reviewed By: varun

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D9931