Fix issues with disabled puzzle steps not registering with puzzle manager

Assets/Scripts/PuzzleS/PuzzleManager.cs

@@ -179,6 +179,14 @@ public class PuzzleManager : MonoBehaviour
         }
     }
 
+    /// <summary>
+    /// Returns whether a step is already unlocked.
+    /// </summary>
+    public bool IsStepUnlocked(PuzzleStepSO step)
+    {
+        return unlockedSteps.Contains(step);
+    }
+
     void OnApplicationQuit()
     {
         _isQuitting = true;