fix(gateway): remove duplicate OnVoiceChannelStatusUpdate method definitions

Fixed CS0111 build error caused by duplicate OnVoiceChannelStatusUpdate method definitions in EventDispatcherExtensions.cs. The methods were defined twice (lines 679-686 and 1013-1020). Removed the duplicate definitions at lines 1008-1020, keeping the original async and sync overloads.

Author: M1tsumi

src/PawSharp.Gateway/Events/EventDispatcherExtensions.cs

@@ -1005,20 +1005,6 @@ public static IDisposable OnIntegrationDelete(this EventDispatcher dispatcher, F
     public static IDisposable OnIntegrationDelete(this EventDispatcher dispatcher, Action<IntegrationDeleteEvent> handler)
         => dispatcher.On("INTEGRATION_DELETE", handler);
 
-    // Voice Channel Status Events
-
-    /// <summary>
-    /// Subscribes to VOICE_CHANNEL_STATUS_UPDATE events.
-    /// </summary>
-    public static IDisposable OnVoiceChannelStatusUpdate(this EventDispatcher dispatcher, Func<VoiceChannelStatusUpdateEvent, Task> handler)
-        => dispatcher.On("VOICE_CHANNEL_STATUS_UPDATE", handler);
-
-    /// <summary>
-    /// Subscribes to VOICE_CHANNEL_STATUS_UPDATE events (synchronous).
-    /// </summary>
-    public static IDisposable OnVoiceChannelStatusUpdate(this EventDispatcher dispatcher, Action<VoiceChannelStatusUpdateEvent> handler)
-        => dispatcher.On("VOICE_CHANNEL_STATUS_UPDATE", handler);
-
     // User Events
 
     /// <summary>