Fix home page crash (2)

[cewert]

Prevent crash by validating node ref and recreating as needed. Comes from roku.com crash log:

Invalid value for left-side of expression. (runtime error &he4) in pkg:/components/home/HomeItem.brs(48) 
Backtrace: 
#0  Function itemcontentchanged() As Voi$1 file/line: pkg:/components/home/HomeItem.brs(49) 
Local Variables: 
global           Interface:ifGloba$1 m                roAssociativeArray refcnt=2 count:14 
itemdata         roSGNode:HomeData refcnt=1 
localglobal      roSGNode:Node refcnt=2 
playedindicatorleftposition <uninitialized> 
extraprefix      <uninitialized> 
textextra        <uninitialized>

which points to this line after running build-prod on 2.1.2:

m.backdrop.width = itemData.imageWidth

Issues

Ref #1164