Fix a few exploits allowing safe consumption of mutant meat (#35573)

* Change cooked meat's copy-from value
Cooked meat had

"copy-from": "meat"

which meant that it had by extension

"cooks-like": "meat_cooked"

which was causing weird behavior, like an exploit where mutant meat did
not have negative effects if dehydrated before cooking.

* Remove NUTRIENT_OVERRIDE from
Several methods of meat preservation were removing toxins from food.
This was because those foods were inheriting NUTRIENT_OVERRIDE, which
was unnecessary thanks to the cooks-like property.

data/json/items/comestibles/carnivore.json

@@ -209,15 +209,16 @@
   },
   {
     "id": "meat_cooked",
-    "copy-from": "meat",
+    "copy-from": "flesh",
+    "weight": "296 g",
+    "volume": "250 ml",
+    "spoils_in": "1 day",
     "type": "COMESTIBLE",
     "name": "cooked meat",
     "description": "This is a chunk of freshly cooked meat.  It's filling and nutritious, but unseasoned and a bit bland.",
-    "proportional": { "price": 1.5 },
+    "price": 750,
     "parasites": 0,
     "calories": 402,
-    "healthy": 0,
-    "fun": 0,
     "vitamins": [ [ "vitC", 16 ], [ "calcium", 2 ], [ "iron", 69 ], [ "vitB", 778 ] ],
     "flags": [ "EATEN_HOT", "NUTRIENT_OVERRIDE" ]
   },

data/json/items/comestibles/meat_dishes.json

@@ -816,6 +816,7 @@
     "description": "Meat slices cured in brine.  Salty but tasty in a pinch.",
     "price": 500,
     "material": "flesh",
+    "delete": { "flags": [ "NUTRIENT_OVERRIDE" ] },
     "primary_material": "cured_meat",
     "fun": 2
   },
@@ -966,6 +967,7 @@
     "healthy": 1,
     "description": "This is a serving of crisply brined and canned meat.  Tasty and nutritious.",
     "price": 250,
+    "delete": { "flags": [ "NUTRIENT_OVERRIDE" ] },
     "fun": 6
   },
   {
@@ -992,6 +994,7 @@
     "color": "light_red",
     "description": "Reconstituted meat flakes, which are much more enjoyable to eat now that they have been rehydrated.",
     "price": 900,
+    "delete": { "flags": [ "NUTRIENT_OVERRIDE" ] },
     "fun": 2
   },
   {