Make cron task no notice on success (#19221)

Change all cron tasks to make them no notice on success default. Instead if a user
wants notices on success they need to add NOTICE_ON_SUCCESS=true instead.

 ## ⚠️ BREAKING ⚠️

This changes the cron config so that notices on success are no longer set by default
and breaks NO_SUCCESS_NOTICE settings. Instead users who want notices on success
must set NOTICE_ON_SUCCESS=true instead.

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Update custom/conf/app.example.ini

Co-authored-by: Norwin <noerw@users.noreply.github.com>

Co-authored-by: Norwin <noerw@users.noreply.github.com>

services/cron/tasks_basic.go

@@ -28,10 +28,9 @@ func registerUpdateMirrorTask() {
 
 	RegisterTaskFatal("update_mirrors", &UpdateMirrorTaskConfig{
 		BaseConfig: BaseConfig{
-			Enabled:         true,
-			RunAtStart:      false,
-			Schedule:        "@every 10m",
-			NoSuccessNotice: true,
+			Enabled:    true,
+			RunAtStart: false,
+			Schedule:   "@every 10m",
 		},
 		PullLimit: 50,
 		PushLimit: 50,