Don't reset size for children

mods/ENTITIES/mcl_mobs/api.lua

@@ -3593,7 +3593,7 @@ local mob_activate = function(self, staticdata, def, dtime)
 	if not self.nametag then
 		self.nametag = def.nametag
 	end
-	if not self.custom_visual_size then
+	if not self.custom_visual_size and not self.child then
 		-- Remove saved visual_size on old existing entites.
 		-- Old entities were 3 now it's 1.
 		self.visual_size = nil