Account for the case where a FocusableNode has an empty outerRects array

In this case boundingRect will be null, so don't try to modify it.
Also, ve.getStartAndEndRects() will return null, so check that too.

Bug: 70777
Change-Id: If67fe35b540b667d85b21f9bbbbe6a73caac2ddb
Merge "Account for the case where a FocusableNode has an empty outerRects array"