[commtest] Add tests for Identity device list
Summary:
Added integration tests for device list. I ended up with a single integration test that tests the following:
- Adding devices during register
- Adding devices during login
- Removing devices on logout
- Reordering devices so mobile is the primary device when possible
- Getting device list updates for another user and verifying their order
Depends on D10421
Test Plan: CommTest, CI
Reviewers: michal, kamil, varun
Reviewed By: kamil, varun
Subscribers: ashoat, tomek
Differential Revision: https://phab.comm.dev/D10422