Allow for GM ticket response text up to 15999 characters.

src/server/game/Tickets/TicketMgr.cpp

@@ -144,11 +144,24 @@ void GmTicket::SendResponse(WorldSession* session) const
     data << uint32(1);          // responseID
     data << uint32(_id);        // ticketID
     data << _message.c_str();
-    data << _response.c_str();
-    // 3 null strings (unused)
-    data << uint8(0);
-    data << uint8(0);
-    data << uint8(0);
+
+    size_t len = _response.size();
+    char const* s = _response.c_str();
+
+    for (int i = 0; i < 4; i++)
+    {
+        if (len)
+        {
+            size_t writeLen = std::min<size_t>(len, 3999);
+            data.append(s, writeLen);
+
+            len -= writeLen;
+            s += writeLen;
+        }
+
+        data << uint8(0);
+    }
+
     session->SendPacket(&data);
 }