Right-align short shelf for split shade when minimalism enabled

Align the short shelf to the right (left when RTL) side for split shade
on lock screen when the notification minimalism is enabled.

Bug: 357643925
Flag: com.android.server.notification.notification_minimalism
Test: manual, verify split shade on lock screen
Change-Id: I7129529ef9382c2c9bb7d7a63e0b7b7e255643fb