Fix launcher crash after restore with some specific widgets.

The internal implementation of PendingAppWidgetHostView#getDefaultViews
uses the same view across updates which causes the exception in
AppWidgetHostView#applyContent when it tries to call addView() because
the view has already been added to its parent view in previous iteration.

Bug: 151901506
Test: manual
Change-Id: Ieccec814ac514e592d0d4f196b60ba89aec0d661