feat:3720: add ntfy to allow-in-powersave
Description
As it has been done on eDrive, Advanced-Privacy, ... we pursue the effort of removing the persistent flag on apps which aren't required for basic use of the system. Setting flag allow-in-powersave to foundation.e.ntfy is one step which allows this.
Issues
https://gitlab.e.foundation/e/os/backlog/-/issues/3720