[lib] rename PrimaryDeviceLogout -> DeviceLogout

Summary:
we plan to reuse this message for both primary device logout and logging out a single secondary device from the primary device.

Depends on D13037

Test Plan: Rename so just ran flow

Reviewers: ashoat, bartek, kamil

Reviewed By: bartek

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D13038