Allow RemoteViews to silently fail when a view can't be found.

Generally, I'm not a huge fan of allowing bugs like this, but this
will allow people to write apps with better compatibility across
configurations. They can just add a bunch of actions, and have
only some of them apply based on which views are in the layout
resource.

Bug: 3107945
Change-Id: Iecb118ce5f56421ac53a7b95ea470de9f726ee82