fix: expand set of never kept items on death

[iProdigy]

• Amulet of the damned (full) can be kept on death; the degraded variant cannot
• Magic butterfly net is never kept on death (1000gp store value)
• Add some other low value (e.g., 1gp) items that are never kept on death

https://oldschool.runescape.wiki/w/Death#Exceptions

[Felanbird]

I've died with jar generator and magic butterfly net before, they are indeed lost.

The other ones require going slightly out of the way to replace, so I'll just believe the wiki