Move registerActionsCleanup to initActionsTasks (#31721)

There's already `initActionsTasks`; it will avoid additional check for
if Actions enabled to move `registerActionsCleanup` into it.

And we don't really need `OlderThanConfig`.

(cherry picked from commit f989f464386139592b6911cad1be4c901eb97fe5)

services/cron/tasks_actions.go

@@ -19,6 +19,7 @@ func initActionsTasks() {
 	registerStopEndlessTasks()
 	registerCancelAbandonedJobs()
 	registerScheduleTasks()
+	registerActionsCleanup()
 }
 
 func registerStopZombieTasks() {
@@ -63,3 +64,13 @@ func registerScheduleTasks() {
 		return actions_service.StartScheduleTasks(ctx)
 	})
 }
+
+func registerActionsCleanup() {
+	RegisterTaskFatal("cleanup_actions", &BaseConfig{
+		Enabled:    true,
+		RunAtStart: true,
+		Schedule:   "@midnight",
+	}, func(ctx context.Context, _ *user_model.User, _ Config) error {
+		return actions_service.Cleanup(ctx)
+	})
+}