Fix AI not shutting down their operator (#1176)

Was banging my head against the wall for this because I R dumb.
It only ever popped up when large numbers of AI were spawned in.

Co-authored-by: Metal Gear Sloth <metalgearsloth@gmail.com>

Content.Server/AI/Operators/AiOperator.cs

@@ -5,6 +5,7 @@ namespace Content.Server.AI.Operators
 {
     public abstract class AiOperator
     {
+        public bool HasStartup => _hasStartup;
         private bool _hasStartup = false;
         private bool _hasShutdown = false;