Resolve @iiSaLMaN 's suggested changes

osu.Game/Screens/Play/PlayerLoader.cs

@@ -536,13 +536,5 @@ namespace osu.Game.Screens.Play
                 };
             }
         }
-
-        /// <summary>
-        /// Sets <see cref="muteWarningShownOnce"/> to false, reserved for testing.
-        /// </summary>
-        public static void ResetNotificationLock()
-        {
-            muteWarningShownOnce = false;
-        }
     }
 }