Emacs: Do not try to fetch built-in packages

.config/emacs/config.org

@@ -913,6 +913,7 @@ Debug Adapter Protocol.
   (mu4e-alert-enable-notifications))
 
 (use-package smtpmail ; built-in
+  :ensure nil
   :init (setq smtpmail-default-smtp-server "mail.riyyi.com")
   :config
   (setq smtpmail-smtp-server "mail.riyyi.com")
@@ -922,9 +923,11 @@ Debug Adapter Protocol.
   (setq smtpmail-queue-mail nil))
 
 (use-package sendmail ; built-in
+  :ensure nil
   :config (setq send-mail-function 'smtpmail-send-it))
 
 (use-package message ; built-in
+  :ensure nil
   :config
   (setq message-kill-buffer-on-exit t)
   (setq message-send-mail-function 'smtpmail-send-it))