fix(battery): Fix battery holder accepting technic charges

Author: pyrollo

nodes/node_battery_holder.lua

@@ -75,11 +75,9 @@ local def = {
 
 			-- Allow all items with energy storage from technic mod
 			if technic.power_tools[node_name] ~= nil then
-				local meta = stack:get_metadata()
-				local md = minetest.deserialize(meta)
 				-- And specifically if they hold any charge
 				-- Disregard empty batteries, the player should know better
-				if md and md.charge > 0 then
+				if stack:get_meta():get_int("technic:charge") > 0 then
 					if digtron.check_protected_and_record(pos, player) then
 						return 0
 					end