Added ChangeMailStarNotify (change importance level)

src/main/java/emu/grasscutter/server/packet/recv/HandlerChangeMailStarNotify.java

+package emu.grasscutter.server.packet.recv;
+
+import emu.grasscutter.game.Mail;
+import emu.grasscutter.net.packet.Opcodes;
+import emu.grasscutter.net.packet.PacketHandler;
+import emu.grasscutter.net.packet.PacketOpcodes;
+import emu.grasscutter.net.proto.ChangeMailStarNotifyOuterClass;
+import emu.grasscutter.server.game.GameSession;
+import emu.grasscutter.server.packet.send.PacketMailChangeNotify;
+
+import java.util.ArrayList;
+import java.util.List;
+
+@Opcodes(PacketOpcodes.ChangeMailStarNotify)
+public class HandlerChangeMailStarNotify extends PacketHandler {
+
+    @Override
+    public void handle(GameSession session, byte[] header, byte[] payload) throws Exception {
+        ChangeMailStarNotifyOuterClass.ChangeMailStarNotify req = ChangeMailStarNotifyOuterClass.ChangeMailStarNotify.parseFrom(payload);
+
+        List<Mail> updatedMail = new ArrayList<>();
+
+        for (int mailId : req.getMailIdListList()) {
+            Mail message = session.getPlayer().getMailById(mailId);
+            int messageIndex = session.getPlayer().getMailIndex(message);
+
+            message.importance = req.getIsStar() == true ? 1 : 0;
+
+            session.getPlayer().replaceMailByIndex(messageIndex, message);
+            updatedMail.add(message);
+        }
+
+        session.send(new PacketMailChangeNotify(session.getPlayer(), updatedMail));
+    }
+}

src/main/java/emu/grasscutter/server/packet/recv/HandlerGetAllMailReq.java

@@ -18,5 +18,4 @@ public class HandlerGetAllMailReq extends PacketHandler {
         GetAllMailReqOuterClass.GetAllMailReq req = GetAllMailReqOuterClass.GetAllMailReq.parseFrom(payload);
         session.send(new PacketGetAllMailRsp(session.getPlayer(), req.getIsGiftMail()));
     }
-
 }