Support sign-in title variant 'Use your saved password for <app>?'

So far we have variant:
- Use your saved passkey for <app>?
- Use your sign-in for <app>?
- Choose a sign-in for <app>?
This change adds:
- Use your saved password for <app>?

Bug: 280483679
Test: manual (see screenshots in bug)
Change-Id: I7aa953ef6a0ec737e2ec51af4f6e2a8cc7b10c30