Invisible Vines Fix (#18196)

* fixes invisible vines bug

* cl

code/modules/hydroponics/seed.dm

@@ -843,6 +843,6 @@
 		var/image/I = image(res.icon, "[get_trait(TRAIT_PLANT_ICON)]-[growth_stage]-leaves")
 		I.color = get_trait(TRAIT_LEAVES_COLOUR)
 		I.appearance_flags = RESET_COLOR
-		res.overlays += I
+		res.add_overlay(I)
 
 	return res

code/modules/hydroponics/spreading/spreading.dm

@@ -100,7 +100,8 @@
 
 	name = seed.display_name
 	max_health = round(seed.get_trait(TRAIT_ENDURANCE)/2)
-	if(seed.get_trait(TRAIT_SPREAD)==GROWTH_VINES)
+	if(seed.get_trait(TRAIT_SPREAD) == 2)
+		mouse_opacity = 2
 		max_growth = VINE_GROWTH_STAGES
 		growth_threshold = max_health/VINE_GROWTH_STAGES
 		growth_type = seed.get_growth_type()