Fix work profile security challenge screen isn't properly shown

Bug: 285111529
Test: 1. Use "Set up TestDPC..." launcher icon to create a work profile. After finishing you should see "personal" and "work" tabs in the all apps list in launcher.
      2. Go to setting -> security & privacy -> more security & privacy -> untoggle "use one lock" to add a work password/pin/pattern.
      3. Install and set up some app that can generate notifications into the work profile (e.g. a messaging app).
      4. Turn the screen off and on to lock the profile.
      5. Receive a notification with that work app, tap on it.
Change-Id: I768f47369b61390580c6a2752edf7d1b53f9af9a