Remove obsolete valid check

core/src/mindustry/world/blocks/distribution/CraterConveyor.java

@@ -265,11 +265,6 @@ public class CraterConveyor extends Block implements Autotiler{
             ||  (tile.front() == source));
         }
 
-        @Override
-        public boolean isValid(){
-            return !dead && (added || sleeping);
-        }
-
         @Override
         public void write(Writes write){
             super.write(write);