Stacks check for invalid amounts (#91656)

## About The Pull Request
Alleviates #91603

As in it does not fix it because i have not been able to reproduce it.
It now checks for invalid values and defaults to `amount`(which is 1)
during `Initialize()` and not null so we don't have to pass the number
`1` when creating a single sheet.
 
A stack trace is thrown for <= 0 sheet amounts so we can debug & fix
stuff

## Changelog
🆑
code: stacks error on invalid amounts, removed manual passing of number
`1` when creating a single stack in many cases
/🆑

code/game/objects/items/stacks/stack.dm

@@ -72,9 +72,11 @@
 	/// or until the cut heals, whichever comes first
 	var/absorption_rate
 
-/obj/item/stack/Initialize(mapload, new_amount, merge = TRUE, list/mat_override=null, mat_amt=1)
-	if(new_amount != null)
-		amount = new_amount
+/obj/item/stack/Initialize(mapload, new_amount = amount, merge = TRUE, list/mat_override=null, mat_amt=1)
+	amount = new_amount
+	if(amount <= 0)
+		stack_trace("invalid amount [amount]!")
+		return INITIALIZE_HINT_QDEL
 	while(amount > max_amount)
 		amount -= max_amount
 		new type(loc, max_amount, FALSE, mat_override, mat_amt)