校验：count不应为负数的校验

game-server/app/servers/chat/handler/chatHandler.ts

@@ -117,6 +117,7 @@ export class ChatHandler {
     async getPrivateMessage(msg: { targetRoleId: string, fromSeqId: number, count: number }, session: BackendSession) {
         const roleId = session.get('roleId');
         const { targetRoleId, fromSeqId = Infinity, count = DEFAULT_MSG_PER_PAGE } = msg;
+        if( count < 0) return resResult(STATUS.WRONG_PARMS);
         const msgs = await getPrivateMessages(roleId, targetRoleId, fromSeqId, count);
         const targetRoleInfo = await getSimpleRoleInfo(targetRoleId);
         return resResult(STATUS.SUCCESS, { targetRoleId, msgs, targetRoleInfo });