Replace invis drawable when ConstantState null

The invisible drawable tried to create a new drawable before, even when
the ConstantState was null. This caused an exception. Now we check for
null pointer, and default to the provided drawable.

Flag: ACONFIG com.android.systemui.qs_new_tiles DEVELOPMENT
Bug: 339201022
Test: Ran the failing build on abtd. The fatal exception did not happen.
Test: atest QSTileImplTest QSIconViewImplTest

Change-Id: I11e6d0d23e3ba005270aff39f111a8bf4c417d55