bowls/mushroom bowls now use fill icon stuff for their fillings (#2567)

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## About The Pull Request

Fixes mushroom bowl becoming invisible/getting weird filling overlay
since it's inheriting the normal bowl's behavior.


![image](https://github.com/shiptest-ss13/Shiptest/assets/24857008/51e17b94-8142-486f-937b-a2b2507457cf)

## Why It's Good For The Game

fixes #2508

## Changelog

🆑 
fix: mushroom bowls no longer become invisible when reagents are
transferred from them
/🆑

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code/modules/food_and_drinks/food/customizables.dm

@@ -304,6 +304,9 @@
 	reagent_flags = OPENCONTAINER
 	custom_materials = list(/datum/material/glass = 500)
 	w_class = WEIGHT_CLASS_NORMAL
+	fill_icon = 'icons/obj/food/soupsalad.dmi'
+	fill_icon_state = "fullbowl"
+	fill_icon_thresholds = list(1)
 
 /obj/item/reagent_containers/glass/bowl/attackby(obj/item/I,mob/user, params)
 	if(istype(I, /obj/item/reagent_containers/food/snacks))
@@ -323,22 +326,6 @@
 		. = ..()
 	return
 
-/obj/item/reagent_containers/glass/bowl/on_reagent_change(changetype)
-	..()
-	update_appearance()
-
-/obj/item/reagent_containers/glass/bowl/update_icon_state()
-	if(!reagents || !reagents.total_volume)
-		icon_state = "bowl"
-	return ..()
-
-/obj/item/reagent_containers/glass/bowl/update_overlays()
-	. = ..()
-	if(reagents && reagents.total_volume)
-		var/mutable_appearance/filling = mutable_appearance('icons/obj/food/soupsalad.dmi', "fullbowl")
-		filling.color = mix_color_from_reagents(reagents.reagent_list)
-		. += filling
-
 #undef INGREDIENTS_FILL
 #undef INGREDIENTS_SCATTER
 #undef INGREDIENTS_STACK

code/modules/mining/lavaland/ash_flora.dm

@@ -458,18 +458,7 @@
 	desc = "A bowl made out of mushrooms. Not food, though it might have contained some at some point."
 	icon = 'icons/obj/lavaland/ash_flora.dmi'
 	icon_state = "mushroom_bowl"
-
-/obj/item/reagent_containers/glass/bowl/mushroom_bowl/update_overlays()
-	. = ..()
-	if(reagents && reagents.total_volume)
-		var/mutable_appearance/filling = mutable_appearance('icons/obj/lavaland/ash_flora.dmi', "fullbowl")
-		filling.color = mix_color_from_reagents(reagents.reagent_list)
-		. += filling
-
-/obj/item/reagent_containers/glass/bowl/mushroom_bowl/update_icon_state()
-	if(!reagents || !reagents.total_volume)
-		icon_state = "mushroom_bowl"
-	return ..()
+	fill_icon = 'icons/obj/lavaland/ash_flora.dmi'
 
 /obj/item/reagent_containers/glass/bowl/mushroom_bowl/attackby(obj/item/I,mob/user, params)
 	if(istype(I, /obj/item/reagent_containers/food/snacks))