[flexiglass] Ribbon is always on in Flexi.

There are too many cases where the ribbon fails to show up; this removes
the conditionality and just always shows the ribbon when Flexiglass is
on. When the time comes, we can remove it.

Bug: 299340392
Test: manually verified that the ribbon is always on when flexiglass is
on
Flag: ACONFIG com.android.systemui.scene_container DEVELOPMENT

Change-Id: If970d9050d06e31eaca89baa4f8b56e1a097a97c