[Core] remove dupe code

Author: Szzrain

Lagrange.Core/Common/Entity/BotGroupNotificationType.cs

@@ -3,6 +3,7 @@ namespace Lagrange.Core.Common.Entity;
 public enum BotGroupNotificationType
 {
     Join = 1,
+    GroupInvite = 2,
     SetAdmin = 3,
     KickOther = 6,
     KickSelf = 7,

Lagrange.Core/Internal/Events/System/SetGroupInviteSelfAcceptEvent.cs

@@ -56,7 +56,7 @@ public async Task GroupMemberRename(long groupUin, long targetUin, string name)
 
     public async Task SetGroupInviteSelfAccept(long groupUin, long sequence)
     {
-        await context.EventContext.SendEvent<SetGroupInviteSelfAcceptEventResp>(new SetGroupInviteSelfAcceptEventReq(groupUin, sequence));
+        await context.EventContext.SendEvent<SetGroupNotificationEventReq>(new SetGroupNotificationEventReq(groupUin, (ulong)sequence, BotGroupNotificationType.GroupInvite, GroupNotificationOperate.Allow, String.Empty));
     }
 
     public async Task GroupQuit(long groupUin)