Fix incorrect placement of HUN icon in statusbar

Flag: ACONFIG com.android.systemui.notifications_icon_container_refactor
DEVELOPMENT
Bug: 278765923
Fixes: 307904590
Test: manual
 1. Receive a heads up notification
 2. Verify icon and text appear correctly in the status bar, without
    overlap

Change-Id: I557f43c3a9c7dab965a2c1f3f0e5f6139da14fb0