Fix mail system setting and remove email from update settings

config/default/sync/system.mail.yml

 interface:
-  default: php_mail
+  default: SMTPMailSystem
 _core:
   default_config_hash: rYgt7uhPafP2ngaN_ZUPFuyI4KdE0zU868zLNSlzKoE

config/default/sync/update.settings.yml

@@ -6,8 +6,7 @@ fetch:
   max_attempts: 2
   timeout: 30
 notification:
-  emails:
-    - admin@example.com
+  emails: { }
   threshold: all
 _core:
   default_config_hash: 2QzULf0zovJQx3J06Y9rufzzfi-CY2CTTlEfJJh2Qyw