request: add "can reset vaults" functionality that's on several other vault keys to "decrepit key"

[Azutte]

• the citadel structure in iron's spells n' spellbooks has trial spawners and vaults in it
• the boss drops a key for the structure's vaults on the floor below the arena
• keys from vanilla vaults say "can reset vaults" on them
• keys from the "kisegi sanctuary" structure say it on them as well, though they only work for vaults from that structure (also while I'm here, kisegi sanctuary has never spawned with its top not cut off by the build limit)

while the decrepit key does not share the same texture as trial keys and kisegi sanctuary trial keys, it serves exactly the same functionality in all other ways and this would help keep the map size down, as the boss is resummonable and you wouldn't have to go look for another citadel for more vaults.

[DivineFinal]

Considering adding this with PR #3734

[Azutte]

Tested on citadel vaults specifically, I hope.