Fixed null error if there are no targets

Assets/Entities/Scripts/Targeter.cs

@@ -36,6 +36,8 @@ namespace AsteroidGame.Entities
 
         public bool FindTarget()
         {
+            if (_activeTargetable == null || _activeTargetable.Count == 0) return false;
+
             var currentBestValue = Mathf.Infinity;
             var targetFound = false;