Nugget boxes work as stasis fish cases for Fryish and Fritterish. (#91317)

## About The Pull Request

Requires #91316, atomized into this pr.
This simply adds the `/datum/element/fish_safe_storage` element to
nugget boxes, which will only matter for fryish/fritterish as they are
the only fish that can be put into them.

This does mean the fish inside will heal, which means you can take a few
more bites out of them before they die if you let them sit in the nugget
box for a while.
## Why It's Good For The Game

I think it's funny for the nugget fish to survive in the nugget box.
Showing my friends my pet fryish collection in my nugget box :)
## Changelog
🆑
balance: Nugget boxes work as stasis fish cases for Fryish and
Fritterish.
/🆑

code/game/objects/items/storage/fancy.dm

@@ -480,6 +480,11 @@
 	spawn_count = 6
 	storage_type = /datum/storage/nugget_box
 
+/obj/item/storage/fancy/nugget_box/Initialize(mapload)
+	. = ..()
+	// It's a safe place for the Fryish/Fritterish
+	AddElement(/datum/element/fish_safe_storage)
+
 /*
  * Jar of pickles
  */