nixos/wakapi: replace systemd script with ExecStart

nixos/modules/services/web-apps/wakapi.nix

@@ -143,10 +143,6 @@ in
       ++ optional (cfg.database.dialect == "postgres") "postgresql.target";
       wantedBy = [ "multi-user.target" ];
 
-      script = ''
-        exec ${getExe cfg.package} -config ${settingsFile}
-      '';
-
       serviceConfig = {
         Environment = mkMerge [
           (mkIf (cfg.passwordSalt != null) "WAKAPI_PASSWORD_SALT=${cfg.passwordSalt}")
@@ -157,6 +153,8 @@ in
           (lib.optional (cfg.passwordSaltFile != null) cfg.passwordSaltFile)
           ++ (lib.optional (cfg.smtpPasswordFile != null) cfg.smtpPasswordFile);
 
+        ExecStart = "${getExe cfg.package} -config ${settingsFile}";
+
         User = config.users.users.wakapi.name;
         Group = config.users.users.wakapi.group;