Stop WindSeedClientNotify and PlayerLuaShellNotify from being sent (#582)

src/main/java/emu/grasscutter/net/packet/PacketOpcodes.java

 package emu.grasscutter.net.packet;
 
+import java.util.Arrays;
+import java.util.List;
+
 public class PacketOpcodes {
     // Empty
     public static final int NONE = 0;
@@ -1566,4 +1569,6 @@ public class PacketOpcodes {
     public static final int UNKNOWN_43 = 8877;
     public static final int UNKNOWN_44 = 8983;
     public static final int UNKNOWN_45 = 943;
+
+    public static final List<Integer> BANNED_PACKETS = Arrays.asList(PacketOpcodes.WindSeedClientNotify, PacketOpcodes.PlayerLuaShellNotify);
 }

src/main/java/emu/grasscutter/server/game/GameSession.java

@@ -157,6 +157,12 @@ public class GameSession extends KcpChannel {
     		Grasscutter.getLogger().warn("Tried to send packet with missing cmd id!");
     		return;
     	}
+
+		// DO NOT REMOVE (unless we find a way to validate code before sending to client which I don't think we can)
+		// Stop WindSeedClientNotify from being sent for security purposes.
+		if(PacketOpcodes.BANNED_PACKETS.contains(packet.getOpcode())) {
+			return;
+		}
     	
     	// Header
     	if (packet.shouldBuildHeader()) {