Fix AwakeMonitor to not duplicates

src/UniTask/Assets/Plugins/UniTask/Runtime/Triggers/AsyncDestroyTrigger.cs

@@ -32,13 +32,11 @@ namespace Cysharp.Threading.Tasks.Triggers
                 if (cancellationTokenSource == null)
                 {
                     cancellationTokenSource = new CancellationTokenSource();
-                }
-
                     if (!awakeCalled)
                     {
                         PlayerLoopHelper.AddAction(PlayerLoopTiming.Update, new AwakeMonitor(this));
                     }
-
+                }
                 return cancellationTokenSource.Token;
             }
         }