Password settings: Fix work profile

Currently, the work profile password settings just point to the personal
profile app. This change fixes this using the forWork metadata tag, that
sets the work profile user in BasePreferenceController.

Also fixes and re-enables the
displayPreference_withPasswords_addsPreference test.

Fix: 192417100
Test: manual - work profile link works, password count is accurate
Test: atest PasswordsPreferenceControllerTest
Change-Id: I6345b69b9c03ff13b8e2784e69dc0188abc436e3