Prevent home screen crash. Validate user setting data

[cewert]

Comes from roku.com crash log:

textextra        <uninitialized> 
extraprefix      <uninitialized> 
playedindicatorleftposition <uninitialized> 
localglobal      roSGNode:Node refcnt=2 
itemdata         roSGNode:HomeData refcnt=1 
m                roAssociativeArray refcnt=2 count:15 
global           Interface:ifGloba$1 Local Variables: 
   file/line: pkg:/components/home/HomeItem.brs(87) 
#0  Function itemcontentchanged() As Voi$1 Backtrace: 
Type Mismatch. Operator "not" can't be applied to "Invalid". (runtime error &h18) in pkg:/components/home/HomeItem.brs(87)

which points to this line after running build-prod on 2.1.4:

if not localGlobal.session.user.settings["ui.tvshows.disableUnwatchedEpisodeCount"]

Issues

Ref #1164