(084340338) Add an aim timer before the weapon can be used. Fix a null reference exception.

Barotrauma/BarotraumaShared/Source/Characters/AI/Objectives/AIObjectiveIdle.cs

@@ -73,6 +73,21 @@ namespace Barotrauma
             }
         }
 
+        public override void Update(float deltaTime)
+        {
+            if (objectiveManager.CurrentObjective == this)
+            {
+                if (randomTimer > 0)
+                {
+                    randomTimer -= deltaTime;
+                }
+                else
+                {
+                    SetRandom();
+                }
+            }
+        }
+
         public override bool IsCompleted() => false;
         public override bool CanBeCompleted => true;