[lib] Introduce a restore flow flag

Summary:
This flag is used to decide if we show the restore button.

https://linear.app/comm/issue/ENG-9679/create-a-screen-where-user-can-choose-between-usernamepassword-and

Test Plan: Flow

Reviewers: kamil, angelika, bartek

Reviewed By: kamil

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D13905