Remove extraneous invalidate call that unregisters AssetManagers

We are already taking care of updating AssetManagers affected by
path changes to a running app's ApplicationInfo. There is no need
to invalidate ALL AssetManagers, thereby unregistering them
from ResourcesManager and preventing configuration changes from
reaching them.

Bug: 64004601
Test: manual
Change-Id: I39311ec9b1dfd34eb7025836f75c92e0516bc36b