wakeonlan service: use powerUpCommands

powerDownCommands is supposed to run before shutdown, but the current
implementation only runs before-sleep, thus not enabling wakeonlan on
devices when powering off even if the hardware supports it.

Taking into consideration the possibility of unexpected shutdown, it is
preferable to move the commands to powerUpCommands instead which is
executed at boot time as well as after resume - that should cover all
use cases for wakeonlan.

Fixes #91352

nixos/modules/services/networking/wakeonlan.nix

@@ -51,6 +51,6 @@ in
 
   ###### implementation
 
-  config.powerManagement.powerDownCommands = lines;
+  config.powerManagement.powerUpCommands = lines;
 
 }