prevent 'core:empty' item drop

res/content/base/modules/util.lua

@@ -1,6 +1,9 @@
 local base_entities = {}
 
 function base_entities.drop(ppos, itemid, count, pickup_delay)
+    if itemid == 0 or not itemid then
+        return nil
+    end
     return entities.spawn("base:drop", ppos, {base__drop={
         id=itemid,
         count=count,