Revert "tech: remove unused code"

This reverts commit d9131be0a5fa501445133fbd6fa25902b9ccc6c0.

pkg/services/alerting/notifier.go

@@ -31,6 +31,10 @@ func (n *RootNotifier) NeedsImage() bool {
 	return false
 }
 
+func (n *RootNotifier) PassesFilter(rule *Rule) bool {
+	return false
+}
+
 func (n *RootNotifier) GetNotifierId() int64 {
 	return 0
 }