Fix crash when switching item with arrow keys.
Fix crash when switching item with arrow keys.

Check that the item id is not a floor before getting its image.

viroulep/RebirthItemTracker,sillypears/RebirthItemTracker,Zamiell/RebirthItemTracker,Hyphen-ated/RebirthItemTracker,viroulep/RebirthItemTracker,BrandonNowlin/RebirthItemTracker,BrandonNowlin/RebirthItemTracker,ArcticJoey/RebirthItemTracker,Hyphen-ated/RebirthItemTrackerTest,Brett824/RebirthItemTracker,johndrinkwater/RebirthItemTracker