[flexiglass] Splits up PIN user input when split layout.

When using the PIN auth method on a folded device in landscape mode, we
get the split layout, where half the bouncer is one side and the other
half is on the other; the PIN entry area (the keypad) needs to be on the
right but the PIN output area (where the dots and shapes appear as the
user enters the PIN) needs to be on the other side, between the message
and emergency button.

Bug: 304630105
Test: please see comment #5 on the attached bug
Flag: ACONFIG com.android.systemui.scene_container DEVELOPMENT
Change-Id: Ia80e011dd6de25128aff072f8d1fe5d0843bbbcf