Exclude WindowInsets.Type.ime() from credential UI

Prevent the credential UI from resizing when the IME appears
or disappeares. Fixes the issue where the window behind us is
briefly shown behind the IME area, before the IME is fully
animated in.

Fixes: 157910732

Test: atest com.android.systemui.biometrics
Test: 1) Set up work profile, set up separate challenge (password)
      2) Open work profile app, close app, lock screen
      3) Open work profile app, go to credential UI, toggle IME
         multiple times. Window behind (launcher) is not seen
Change-Id: Id5b9a43fb76a63063abe64c578d7fa3492be4bdd